Autosplice can now supply a field-installable retrofit kit that allows customers with earlier models of the company’s insertion equipment to upgrade it to include direct drive capabilities.

The kits eliminate the older ac motor, pulley and wrap-spring clutch assemblies, and replace them with faster, quieter and more reliable mechanisms. These result in a reduction in overall system wear and the elimination of unnecessary motion. The direct drive retrofit also improves overall productivity by streamlining the machine set-up process.

http://cnc-info.blogspot.com/search/label/cnc%20retrofit

Specialising in rebuilding, CNC retrofitting and the servicing of precision grinding machines, Industrial Machine Tool Services (IMTS) in Kent has provided many cost effective solutions. abrasiv

Specialising in rebuilding, CNC retrofitting and the servicing of precision grinding machines, Industrial Machine Tool Services (IMTS) in Kent has provided many cost effective solutions in the abrasive machining sector over the last 20 years. A growing portion of the company’s business is now connected with upgrading existing grinding machines by way of retrofitting new controls and drive systems so that customers get all the benefits of the latest technology, but at a more affordable price.

One recent example of such a CNC retrofit concerned a sub-contractor who wanted to improve the efficiency with which it could grind multi-diameter shafts for AC servo-motors.

The company could not justify the cost of buying a new CNC cylindrical grinder for this project and so looked around for a more affordable alternative.

It knew of IMTS’s grinding expertise in the fields of rebuilding and retrofitting and contacted the Rochester-based specialist to see if could handle the project.

In fact, IMTS came up with a complete package solution which included sourcing a good quality used CNC cylindrical grinder and then updating the machine, notably on the control and drives side.

With all his contacts in the grinding field, IMTS managing director Charles Thurston soon tracked down a suitable model - a 1988 Jones and Shipman 1094 CNC cylindrical grinder.

While this straight-approach wheelhead machine was equipped with an old Alan-Bradley control system, it was mechanically very sound as it had been installed in a university and had not been subjected to a great deal of use.

The complete upgrading project involved: stripping the existing machine right down to its carcass, checking all the key elements, retrofitting a new two-axis NUM 1040CNC system and adding Marposs in-process gauging.

This updated cylindrical CNC grinder is now being used to process AC servo motor shafts measuring up to 450 mm long with diameters up to 50mm in batches of 100 off.

Previously, the sub-contractor could only grind one diameter at a time on its manual machine.

But the introduction of the Jones and Shipman CNC model has transformed production efficiency.

For grinding operations can now be performed some three times faster, up to five diameters can be ground in a single operation, set-up times have been significantly reduced, peripheral wheel speeds now reach 35m/sec and the 5 micron tolerance is readily held throughout the entire batch.

What’s more, the complete retrofit project carried out by IMTS provided an affordable and speedy solution to the sub-contractor’s production problem.

For this upgraded machine saved 35% of the cost of a comparable new CNC cylindrical grinder and it was delivered in just seven weeks, as opposed to the six or seven months lead time being quoted for a new cylindrical grinder.

As well as optimising grinding operations on the servomotor shafts, the customer is also now using the machine to grind a range of stainless steel components, too.

Founded in 1981, IMTS has established itself at the forefront of grinding technology by providing a range of specialist services.

These include: complete machine rebuilds, partial rebuilds, CNC retrofitting, on-site service (for both manual and CNC grinders) and the supply of spare parts.

The company works closely with control manufacturer NUM and has developed its own special grinding software.

http://www.manufacturingtalk.com/news/inf/inf100.html

Wood turning has swept the wood working world as the fastest growing part of its methods. This of course has meant the growth of the wood lathe manufacturing industry as more and greater styles of lathe are being made. While this has meant a great deal of choice for the advanced turner with some idea of what he or she may desire in a machine, the buyer of one’s first wood turning lathe may be in for a shock and a quandary over what lathe to buy.

The wood turning web sites do not in general come as any great help. While there are lots of places to learn to turn, most wood turners are self taught and are experienced in using only one lathe, perhaps two if they have upgraded along the way. Also there may be a lot of opinions given from people who have only one turning interest in life. The turner of large bowls who can not imagine that any one would like to turn anything else has a hard time recommending a lathe to someone who wishes to make intricate lace bobbins weighing less than an ounce.

Of course the other side of the picture is the web sites give a glimpse into the world of many kinds of wood turners using many wood turning lathes and making a wide range of round objects. Many of them have at least a picture of their lathes and some have personal reviews of their machines and tooling. It is a good idea for the beginner to get an idea of what is available.

Even better is the local wood turning club. Examine your local paper or bulletin board or contact the American Association of Woodturners which has branches in many countries. Wood turning clubs tend to be some of the friendliest places on earth with a great deal of information mixed with camaraderie. A typical meeting will deal with minimal business, a demonstration of wood turning and a members show and tell. Most clubs have a lathe that can be seen and some have one or more to lend.

Then there are the club members. Most clubs will have people who have turned for years and may be professional as well as intermediate and beginning hobbyists. It is normal for people of all levels to exchange opinions and ideas without prejudice for age or experience. What is more useful still for our discussion is most turners would welcome a newcomer into their midst to come and try their lathe. This is a great way to see what a lathe can do under some experienced instruction. Looking at a series of lathes should give an idea of what you would like to turn and what sort of wood turning lathe you would like to have.

While you are with the other turners do not neglect to get a lesson or two and perhaps a piece of wood. Turners as a group love to teach and each one has something unique to give. As a group they tend to be self taught for the most part, thus opinionated and stubborn over those opinions but great to one another and to anyone who wants to share the addiction. Wood turners and wood turning lathes, in their own way each is the heart of the hobby.

Wood turning lathes seem to be machines on steroids some days. They are getting bigger and more massive all the time. This is likely in response to two trends in the wood turning world. First is the response from manufacturers to a tendency among turners to make bigger and bigger pieces. Second is the prevailing idea that bigger is always better in almost every part of life. Sometimes it is just not so.

Ed Moulthrop was likely not the first to turn large pieces but he became famous for them in the twentieth century. His yard would be filled with huge sections of tree trunk more than three feet in diameter, awaiting their turn on his home made lathe. Most of them would be arranged on a slope above the shop to make them easier to manage when trying to get them indoors. He had to use a block and tackle to get them to and on the lathe and the lathe was home made to get something big enough and slow enough to turn them safely.

Here we get an idea of what the turner of large pieces of wood has to contend with each time a piece goes on the lathe. Wood is heavy and the hardwood that most turners work with is heavier still. When you consider that most of us start with green wood, the weight is even greater. How many people will really want to wrestle with a chunk of wood more than 150 pounds in weight each time they wish to turn? That is a section of log big enough to turn a 24 inch bowl. A 24 inch hollow form will easily start at 300 pounds for the blank. Considering that some turners turn upwards of four foot diameter bowls, the weight is considerable. In maple the blank, assuming you could find a tree 4 feet in diameter, would be about 1200 pounds.

For the average turner, if such a person exists, a big bowl tends to be 12 inches in diameter and for the beginner, 10 inches is a good size. It will hold a lot of salad, is large enough to handle, and can appear more intimidating than it needs to be. Many beginner level lathes will handle a 10 to 11 inch bowl and will generally serve for several years to come.

What is important for the beginner is to obtain a lathe. Be sure it is sturdy enough to use with safety and enjoyment. Wood turning is growing quickly and wood turning lathes for beginners are becoming popular with the manufacturers. This is a good time to begin your enjoyment with a wood turning lathe

Anyone considering the purchase of a new machine tool at IMTS will probably wonder if his current machine could be upgraded. This article explores the three primary types of machine tool upgrades available from builders and third-party specialists: retrofit, rebuild and remanufacture.

Going Retro

The term “retrofit” usually means an upgrade to just the CNC. However, a control upgrade should also include new servomotors, drives, magnetics (motor starters, breakers, solid-state relays, etc.) and a complete rewiring of the machine.

A retrofit costs about 30 percent of the price of a new machine, so the retro candidate must be mechanically sound to justify the investment. The OEM, or reputable third-party rebuilder, can provide a complete mechanical assessment of your machine tool.

Don’t be afraid to pay for a second opinion. It often proves to be money well spent.

An older CNC machine tool undergoing a retrofit probably will have a control installed that incorporates features not available at the time the machine was purchased. Faster data-processing speed means a faster acceleration/deceleration rate and axis motion, and greater positioning accuracy.

These capabilities are what make it wise to upgrade a machine’s servomotors, drives and magnetics during a retrofit. Failing to upgrade the entire system means the user won’t realize the full benefits of his new CNC.

Many older controls have no host-computer communication capabilities, while new CNCs provide a variety of communication options. Today’s controls also have built-in computer diagnostics to assist the operator, programmer and maintenance person when troubleshooting a tooling problem, programming error or machine fault.

A dedicated control just runs the machine tool, while a PC-based CNC can run the machine program and other software simultaneously. Both types have advantages. Familiarize yourself with what each offers in terms of speed, programming features and memory before selecting your new control.

Servos, Drives, Wiring

The predominant servomotor installed on new and upgraded machine tools is the brushless AC motor. It has an excellent power-to-size ratio and requires little or no maintenance. Some dedicated controls mandate the use of both digital servomotors and drives—an excellent combination—in order to upgrade the control.

The drive tuning on a digital system is done via the control screen, with soft parameters; no manual tuning is required. The connections between the drive and CNC are usually serial or fiber optic, a faster and more reliable method than analog connections. Some control and drive manufacturers have joined forces in an effort to develop digital interfaces that can be used with PC-based systems.

Although many successful retrofits are done without replacing the original magnetics system (motor starter, fuses, disconnect, relays, etc.), it’s not recommended. One of the advantages of having a new control, servomotors and drives is that they are significantly smaller than their earlier-generation counterparts. Similarly, the newer magnetics panels are smaller, so they occupy less floor space while meeting modern electrical codes.

Completely replacing the machine wiring also is a highly recommended. Rewiring also ensures that the machine meets modern electrical codes.

Today’s demand for higher spindle speeds raises the issue of whether to replace the spindle motor and drive. The limiting factor for increasing spindle speed is mechanical. You simply cannot put a 6,000-rpm motor in place of an 1,800-rpm motor without causing irreparable damage to the transmission.

But unlike servomotors, there are certain instances where it makes sense (as in dollars and cents) to rebuild the original DC motor and match it to a new digital DC drive. Generally, you should keep a DC system that’s above 30 hp and replace one that’s below 30 hp with a brushless AC system.

Make sure, though, that you consider the base motor speed. Older DC spindle motors have base speeds that range from 500 to 850 rpm, with top speeds of 2,500 to 3,000 rpm. The base speed of a brushless AC motor is usually 1,500 rpm, with maximum speeds as high as 10,000 rpm. If the base speed of the AC motor is three times the old DC motor, then at the original base speed, an AC motor will only generate one-third of the old DC motor’s rated horsepower.

One way around this problem is to change the gear or pulley ratio. But if the motor is directly coupled to the spindle, some engineering work will be needed to make the brushless AC system generate the same low-speed horsepower.

A Rebuilding Season

When the machine tool industry refers to a rebuild, it generally means that all of the mechanical components of the machine are cleaned, inspected and then reassembled using new or remachined components. As with a retrofit, a rebuilt CNC machine costs about one-third the price of a new unit.

Good candidates for a rebuild are machines less than 12 years old that have a reliable CNC, and servomotors, a spindle motor and drives that do not need upgrading. Also, make sure that any unreplaced components are readily available and will continue to be supported for the expected life of the rebuild. Few things are more frustrating than to spend money on a rebuild only to discover later that the spindle-drive manufacturer, for example, no longer produces your machine’s drive.

Any major mechanical upgrade to a machine tool should always include the replacement of all bearings and seals, to OEM specifications.

In addition, the spindle assembly (or cartridge) and/or headstock should be completely disassembled and inspected. All internal bearings should be replaced, including the precision-class spindle bearings. All gears should be checked for wear and cracks. The shafts should be checked for straightness and all of the bearing journals should be repaired as needed. The spindle itself should be reground.

On a milling machine, the spindle taper and face must be reground to OEM specifications. The drawbar should be rebuilt, which includes replacing all of the clamping springs. Lathe spindles should be checked for straightness. The taper must be carefully inspected and, if necessary, reground. The final reassembly should follow the OEM specification for proper runout and endplay.

It’s possible that damage to the spindle/headstock will be too severe to repair, but that cannot be known until it is taken apart and inspected. Fortunately, many of today’s OEMs manufacture and stock replacement spindle assemblies and cartridges.

Another mechanical area to be rebuilt is the way system. The work done here is critical to returning the machine to its original accuracy. The two primary systems used in the machine tool industry are box ways and linear guides.

If your machine has box ways, they should be visually inspected for scoring and checked for hardness. Most new ways have an average hardness of Rc 50 to 63 at a depth of 0.090″ to 0.125″. They should be reground flat, perpendicular and parallel, within 0.0002″ TIR and a 32µin. finish. This level of accuracy is obtained by grinding the ways on a precision bed grinder. The ways should have no less than a 0.050″ depth of hardness after grinding to ensure longevity. If a way has scoring below that depth of hardness, it may have to be scrapped. If the way is integral to the casting, it can sometimes be repaired, but this is not prudent.

Some OEMs make their ways removable. While removable ways can be finish-ground off the machine, they should be reinstalled and then ground in place to ensure the highest possible accuracy.

Hardened-steel box ways incorporate one of three common slide techniques. The first, and most economical, involves the use of a low-friction material like Turcite or Multifil. The existing material is removed from the slide. Then new material is glued in place and the slide is hand-scraped and fitted to the ways.

An alternate technique is to machine the base of the slide to accept a “wear strip.” Then Turcite or Multifil is glued to a piece of spring steel so that it can be removed for fitting. Future replacement of the wear strip is easier because the slide does not need to be removed.

The second type of slide system incorporates linear roller bearings. The roller bearings are placed side by side in a cage that resembles a tank track. The cage is held together with a rubber banding and rides in pockets milled in the slides. The rebuilder should replace these bearings.

If the box ways are made of cast iron rather than steel, they can be reworked by two common methods. One is hand scraping and mating the way to the slide until it reaches the accuracy of the OEM specification. But there are at least three potential downsides to this approach.

One is the machine tool’s feed rate. This metal-to-metal slide method cannot be driven at rapid feed rates much over 200 ipm. Second, this way system is prone to damage from contamination, usually in the form of metal chips that get between the slide and way, causing scoring that severely reduces machine accuracy. Third, the hand scraping of ways is a rapidly disappearing art. If a company offers this service, check customer references for machines that are at least a year beyond their warranty period. You need to be absolutely sure that the company you contract to rebuild your machine knows what it’s doing with respect to scraping ways.

The second method of reworking cast iron box ways is to grind the way to allow Turcite or Multifil to be fitted to the slide. Today’s precision grinders produce highly reliable results and attain excellent surface finishes that meet the OEM specification.

A third type of slide, which is found on larger machines, is the hydrostatic system. With this design, the slide rides on a film of oil at all times. When rebuilding a hydrostatic system, all of the pressure-compensating valves must be replaced. The slide should be checked for a proper fit to the way system and scraped as necessary.

The majority of modern CNC machine tools use linear guides. A linear guide system consists of a pair of rails. On each rail rides two or more bearing packs that are called “trucks,” which attach to the table or column. If they are still in good condition, they can be reused after basic maintenance is performed.

Unlike box ways, linear guides cannot be reground. Linear guide rails and trucks wear as a system. If replacement is needed, insist that both the rails and trucks are replaced.

Ballscrews are the heart of your axis accuracy and can be expensive to replace. But fortunately, most ballscrews can be rebuilt once—sometimes even twice—depending on the amount of wear or damage that must be corrected. This service is generally outsourced by rebuilders to shops that specialize in the manufacture and remanufacture of ballscrews.

The process requires the screw and nut to be disassembled and inspected for hardness, rust and wear. It then can be determined if a repair is possible. A reground ballscrew will be returned with a new nut, while the bearing journals are checked and repaired as necessary. The ballscrew is then reinstalled with new thrust bearings and checked for accuracy to ensure proper height, parallelism and runout.

If a repair is impossible, be aware that new ballscrews can have a lead time of eight to 10 weeks. Remanufactured screws are usually out and back in less than a month.

Checking Fluids

A machine’s hydraulic fluid reservoir should be thoroughly cleaned during any rebuild. The pump and motor should either be rebuilt or replaced, along with any filters or strainers. The flexible hydraulic hoses must also be replaced.

The solenoid valves of a hydraulic system normally do not fail mechanically; a burned-out coil is the usual culprit. Therefore, the decision to replace them during a rebuild is usually made by assessing the risk of obsolescence and whether the valves have been prone to frequent failure in the past.

The central lubrication system is the single most important system on any CNC machine. All of the flexible lube lines must be replaced and all of the metal lines flushed and tested for leaks. The pump should always be replaced.

There are types two of central lube systems on a CNC machine. The one-line resistance system consists of a low-pressure pump that sends a single line of lubricant directly into a manifold. The multiple lines that exit the manifold are routed to individual lubrication points throughout the machine tool. A “metering unit” in each line serves to regulate the rate of oil flow.

A small orifice in the metering unit supplies the proper amount of oil for a given lubrication point. The units come in various sizes, based on the amount of oil that is needed. All metering units must be replaced.

The second lube system is the progressive type, which uses a high-pressure (up to 3,000 psi), air-over-oil pump with individual feeder blocks that contain “spools.” Each time the pump piston fires, these spools are shifted in the blocks, precisely controlling the amount of oil that reaches each lubrication point. A block can sense if a spool has not shifted, sending a lubrication alarm to the CNC.

A progressive system can be completely flushed, inspected and reused. If your machine tool cuts cast iron or other abrasive materials and is equipped with a one-line system, consider converting to a progressive-type system.

Final Approach

Reassembly of a machine being rebuilt begins at the base, with proper leveling. A weight shift occurs as each major component (table, spindle, column, etc.) is added to the base. The risk of accuracy error is significantly reduced when the level is rechecked after each major component is added to the machine base. Geometric alignments should be made using OEM procedures and tolerances.

Proper alignment includes a static check performed with a granite square and electronic levels. By today’s standards, proper alignment also includes a dynamic check with a system that provides a computer-generated analysis of the accuracy of the machine tool in motion. A “ballbar” test ensures that the individual axes are aligned correctly and that the relationships between the axes in motion are also accurate.

Rebirth

The most comprehensive type of machine upgrade is remanufacturing. It combines everything involved in a retrofit and rebuild. Plus, a remanufacture job includes design changes that improve the machine’s performance beyond its original specifications.

These changes could include an increase in the rapid and cutting feed rates, extended axis travels and a higher spindle speed.

At half the cost of a comparably equipped new machine, remanufacturing is only practical when a new replacement machine would cost $400,000 or more.

A typical retrofit that includes a control, servomotors and drives will take four to eight weeks. Most control manufacturers have delivery schedules in the four-to-six-week range, so a control-only retrofit is slightly faster.

The delivery for a complete rebuild should range between 12 and 16 weeks, depending on the extent of the damage and wear to the machine tool. A remanufacture will take five to seven months from the time the machine leaves and returns to your shop floor.

Get It In Writing

Machine tool documentation is a critical element of any machine tool upgrade. The lack of accurate and complete documentation can turn an otherwise good retrofit, rebuild or remanufacture into a disaster when the first problem crops up.

At a minimum, documentation should include high-voltage schematics, all of the input and output diagrams, a complete servo/spindle wiring schematic (including all pin-outs on the plugs), physical machine-view drawings and an operator’s manual.

The last piece of documentation may be controversial, so spell it out in the contract. No machine upgrade is complete without a fully cross-referenced ladder or soft-logic diagram. Some OEMs and third-party specialists believe that this is their proprietary information. But you cannot effectively troubleshoot a CNC machine without it.

All of the documentation should be provided in several formats. Insist on a hard copy with a digital backup written in a commonly available format that can be stored, duplicated or reprinted in-house.

Interview the operators and maintenance mechanics to expose any known problems with machine performance before any work is contracted. In the written agreement, spell out the specific performance problems you expect to be eliminated by whatever upgrade is selected.

Competent firms will give you a list of references and offer to show you machines they have upgraded.

And, lastly, be wary of one “R” that seems to get thrown around a lot these days—refurbishment. Many “refurbished” machines have received little more than a bath and a paint job.
http://www.ctemag.com/article/viewArticle.asp?ARTICLE_ID=265

A three-axis Anilam CNC control system more usually found controlling milling machines has transformed the capability of a rebuilt Jones and Shipman 540 toolroom surface grinder at tooling manufacturer, Electro-spark. The grinder, which before being rebuilt was a manual machine, has enabled the Cwmbran (South Wales) company to reduce cycle times and improve quality levels in the production of components which are now machined under full three-axis (x, y and z) control with the Anilam system. The machine has been completely rebuilt and fitted with DC drives on all three axes, with the drives being controlled by the Anilam MK 3300 CNC.

Also, the original 1.1 kW grinding wheel spindle drive motor has been replaced by a 3.7 kW motor which drives the spindle through a poly-vee belt.

As a result of the new drives and larger motor - and in combination with the fine degree of positional and rotational control provided by the Anilam CNC - the machine is now being used also for creep feed grinding.

The benefit of this is illustrated by Electro-spark managing director, Dave Calder, who quotes one of the first jobs carried out on the refurbished machine.

“The component was previously ground by multiple passes and small downfeed movements of the wheel”, he says.

“With 50 ground in one setup, the production rate was then 350 parts an hour.

On the new machine, however, a 0.020in deep cut is used to enable the work to be completed in one pass and, as a result, throughput has risen to 600 an hour.

Component quality has improved too, because there is no longer the disturbance of the work by wheel contact at the beginning of each pass as with reciprocal grinding.

Also, because of the greater degree of control on feed rate and positioning, it is possible to fast feed the wheel close to the point of cutting before reducing to the creep feed rate.

This has also contributed to the improved cycle time”.

While Electro-spark provides a subcontract tool making service, its primary role is making tooling components for one of its sister companies, Iron-spray, which manufactures tools in volume for use in carpet-making and weaving machines.

It cost Dave Calder GBP 22,000 to have the machine rebuilt and the CNC integrated.

The Anilam retrofitting, which included fitting new ballscrews and drives, was carried out by Machine Tool Control of Pontypool, South Wales - Anilam’s representative in Wales and a specialist in CNC retrofitting with over 20 years experience in the sales and support of the Anilam product range.

“To buy a new CNC machine with a comparable CNC would have cost three times as much, and the machine would have been too big for the light precision work we now do on it”, reckons Dave Calder.

“Due to its success there are now plans to have a second grinding machine rebuilt for control by a two-axis Anilam MK 3200 unit”.

As well as being good value for money, the rebuild and retrofit has provided Electro-spark with a type of machine control well suited to its toolmakers’ style of working.

“It is programmed logically in the way the machine operator thinks”, continues Dave Calder.

“He simply tells the CNC what he thinks the machine needs to do.

He can have a picture of the operations in his mind, as if he were turning the handles.

Nor does making a single movement change to a program affect any other movements that are part of an operating cycle”.

The grinder is permanently fitted with a fixturing system to which all subfixtures accurately locate; this facilitates the transfer of workpieces to milling and EDM machines.

The axial position of the main fixture on the grinder is precisely known so that its relationship to the grinding wheel can be accurately determined by the CNC.

“The operator brings the wheel to where the cutting will start and sets the zero position.

After that, all the movements can be programmed in sequence.

The average job takes about ten minutes and it is so logical.

All the programs we have so far created are stored in the CNC’s ample memory”.

The versatility of the retrofit machine and its new controller is illustrated by one example which involved grinding a group of identical parts as one setup.

When completed on a manual grinder the fixture had a small error in alignment so the height of the last piece differed from the first by 0.002in.

This was compensated for by grinding the middle part to size then the first and last on top and bottom limits.

“We put it on the new machine and programmed the Anilam to give a 0.002in fall along the length of the batch”, says Dave Calder.

“When we checked them they were all parallel and in tolerance.

From then on the operator felt fully at home with the control; it is so user friendly.

I know we should have corrected the fixture in the first place, but now there is no need to”.

In addition to tool steel, tungsten and exotic metals, the machine also grinds ceramics.

For holding these non-magnetic materials, Electro-spark has recently started using the Cryotech ice-chuck.

This system was developed in Switzerland and last year the product and name was purchased by Dave Calder to enable him to manufacture and market the novel workholding device.

The Cryotech ice chuck creates a holding force of 15kg/cm2, sufficient for machining by grinding and other methods.

With the workpiece placed on the wetted chuck surface, the water is frozen using microprocessor control and as it turns to ice it securely holds the workpiece.

The complexity of work now possible on the Jones and Shipman machine, and in this particular instance with the aid of the Cryotech ice chuck, is shown in its ability to grind a very thin plate that has a three-dimensional crowned surface.

This called for the 100mm square plate to be held firmly and to have its top surface crowned in both directions, using both longitudinal and transverse table movements to form part of the spherical surface.

All the wheel and table movements needed to achieve the shape were programmed sequentially into the Anilam CNC by the operator to create the precise form.

http://www.engineeringtalk.com/news/ani/ani110.html

A three-axis Anilam CNC control system more usually found controlling milling machines has transformed the capability of a rebuilt Jones and Shipman 540 toolroom surface grinder at tooling manufacturer, Electro-spark. The grinder, which before being rebuilt was a manual machine, has enabled the Cwmbran (South Wales) company to reduce cycle times and improve quality levels in the production of components which are now machined under full three-axis (X, Y and Z) control with the Anilam system. The machine has been completely rebuilt and fitted with DC drives on all three axes, with the drives being controlled by the Anilam MK 3300 CNC.

Also, the original 1.1kW grinding wheel spindle drive motor has been replaced by a 3.7kW motor which drives the spindle through a poly-vee belt.

As a result of the new drives and larger motor - and in combination with the fine degree of positional and rotational control provided by the Anilam CNC - the machine is now being used also for creep feed grinding.

The benefit of this is illustrated by Electro-spark managing director, Dave Calder, who quotes one of the first jobs carried out on the refurbished machine.

‘The component was previously ground by multiple passes and small downfeed movements of the wheel,’ he says.

‘With 50 ground in one set-up, the production rate was then 350 parts an hour.

‘On the new machine, however, a 0.020in deep cut is used to enable the work to be completed in one pass and, as a result, throughput has risen to 600 an hour.

Component quality has improved too, because there is no longer the disturbance of the work by wheel contact at the beginning of each pass as with reciprocal grinding.

‘Also, because of the greater degree of control on feed rate and positioning, it is possible to fast feed the wheel close to the point of cutting before reducing to the creep feed rate.

This has also contributed to the improved cycle time.’ While Electro-spark provides a sub-contract tool making service, its primary role is making tooling components for one of its sister companies, Iron-spray, which manufactures tools in volume for use in carpet-making and weaving machines.

It cost Dave Calder GBP22,000 to have the machine rebuilt and the CNC integrated.

The Anilam retrofitting, which included fitting new ballscrews and drives, was carried out by Machine tool control of Pontypool, South Wales - Anilam’s representative in Wales and a specialist in CNC retrofitting with over 20 years experience in the sales and support of the Anilam product range.

‘To buy a new CNC machine with a comparable CNC would have cost three times as much, and the machine would have been too big for the light precision work we now do on it,’ reckons Dave Calder.

‘Due to its success there are now plans to have a second grinding machine rebuilt for control by a two-axis Anilam MK 3200 unit.’ As well as being good value for money, the rebuild and retrofit has provided Electro-spark with a type of machine control well suited to its toolmakers’ style of working.

‘It is programmed logically in the way the machine operator thinks,’ continues Dave Calder.

‘He simply tells the CNC what he thinks the machine needs to do.

He can have a picture of the operations in his mind, as if he were turning the handles.

Nor does making a single movement change to a program affect any other movements that are part of an operating cycle.’ The grinder is permanently fitted with a fixturing system to which all sub-fixtures accurately locate; this facilitates the transfer of workpieces to milling and EDM machines.

The axial position of the main fixture on the grinder is precisely known so that its relationship to the grinding wheel can be accurately determined by the CNC.

‘The operator brings the wheel to where the cutting will start and sets the zero position.

After that, all the movements can be programmed in sequence.

The average job takes about ten minutes and it is so logical.

All the programs we have so far created are stored in the CNC’s ample memory.’ The versatility of the retrofit machine and its new controller is illustrated by one example which involved grinding a group of identical parts as one set-up.

When completed on a manual grinder the fixture had a small error in alignment so the height of the last piece differed from the first by 0.002in.

This was compensated for by grinding the middle part to size then the first and last on top and bottom limits.

‘We put it on the new machine and programmed the Anilam to give a 0.002in fall along the length of the batch,’ says Dave Calder.

‘When we checked them they were all parallel and in tolerance.

From then on the operator felt fully at home with the control; it is so user friendly.

I know we should have corrected the fixture in the first place, but now there is no need to.’ In addition to tool steel, tungsten and exotic metals, the machine also grinds ceramics.

For holding these non-magnetic materials, Electro-spark has recently started using the Cryotech ice-chuck.

This system was developed in Switzerland and last year the product and name was purchased by Dave Calder to enable him to manufacture and market the novel workholding device.

The Cryotech ice chuck creates a holding force of 15kg/cm2, sufficient for machining by grinding and other methods.

With the workpiece placed on the wetted chuck surface, the water is frozen using microprocessor control and as it turns to ice it securely holds the workpiece.

The complexity of work now possible on the Jones and Shipman machine, and in this particular instance with the aid of the Cryotech ice chuck, is shown in its ability to grind a very thin plate that has a three-dimensional crowned surface.

This called for the 100mm square plate to be held firmly and to have its top surface crowned in both directions, using both longitudinal and transverse table movements to form part of the spherical surface.

All the wheel and table movements needed to achieve the shape were programmed sequentially into the Anilam CNC by the operator to create the precise form.

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Being the sole manufacturer and number one barfeed supplier in the UK, Hydrafeed have fitted their units to almost every type of CNC lathe available, both in the UK, and overseas. They are the main supplier to all major machine tool dealers in the UK, and are one of the most reliable companies when the question of retrofitting is raised. With over 15 years experience in the field of Barfeed retrofits, the service provided is heavily detailed and completed to the exact specifications set out by the customer at the start of the project.

Before accepting a retrofit project, the Hydrafeed team arranges a convenient visit to the customer1s premises, in order to undertake the following 1.

Obtain photos of the customer’s site.

2) Obtain full measurement details for CNC Lathe.

3) Obtain complete electrical specifications for Interfacing.

4) Obtain details of customer’s job requirements / specifications.

Upon return to site, the Hydrafeed team will then review all the above points, in order to confirm that all criteria can be met, and that the customer can be given the complete package that they have requested.

The team then contacts the customer outlining all costs, time scales, and outlining points that the customer will need to be aware of in order for the whole retrofit to run smoothly.

Over the years, Hydrafeed has retrofitted their Barfeeds to many customers including G-Mach Engineering, John Hall Engineering, and RGS Electro Pneumatics.

Graham Miller of Melton Mowbray based G-Mach Engineering comments, ‘We originally had a long Barfeed on our Lathe, and decided to move in onto another Lathe.

We then contacted Hydrafeed with details on a particular application that we wished to run.

Hydrafeed provided us with a complete package to suit the application we required, and a complete retrofit of one of the Multifeed Short Magazine Barfeeds on to the Hitachi Lathe was undertaken.

Since it1s installation in September last year, the package has not stopped running, and has proved to be extremely useful in cutting cycle times, and increasing turnover.

The retrofit of the Multifeed Barfeed was quick, easy and very professional by Hydrafeed.’ Martin Hall of John Hall Engineering in Bridlington explains, ‘A component drawing was sent to Hydrafeed who quickly diagnosed possible problems with the application.

These problems were resolved almost immediately, and the Multifeed Barfeed was installed on to our Tornado Lathe.

The cycle time has been reduced by 25%, and the machine now runs for 10 hours a day, with the operator running another machine.

From my initial request for literature, through to installation, Hydrafeed have been both efficient and professional.’ Tony Watson of RGS Electro Pneumatics, based in Oswaldthistle reveals, ‘RGS has seven lathes, and operates the machines with 1-2 setter / operators at any one time - two of these lathes had single Barfeeds on them.

We decided to replace the Barfeeds with two Multifeed units, to create longer continuous running, and the facility for lights out running on the two Nakamura TW10s.

We contacted Hydrafeed, and within two weeks from order, the Barfeeds were specified, installed, and interfaced (installation and interfacing carried out over a two day period, including operator training).

This was all done in a very quick, methodical and professional manner from start to finish, and we are now beginning to see the benefits of using Hydrafeed for this retrofit.’ With their highly trained team, a massive wealth of experience in the field of Barfeed retrofitting, and with many satisfied customers, Hydrafeed can provide the complete package to suit all types of applications, providing maximum support and reliability, with minimum effort and worry, all at a price second to none in the Barfeed industry.

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Eaton engineers have reported 11% increase in overall productivity of a Heald grinder, plus improved throughput and enhanced accuracy since retrofitting an up-to-date CNC. Eaton Corporation‚s facility in Roxboro, North Carolina is a major supplier of hydraulic lifters and associated components for the automotive market. A key machine tool in their operation is the Heald 1VL, an I.D.

grinder utilized for the finish grinding operation on these critical engine components.

This Heald grinder was originally equipped with an early generation Siemens 3G CNC, used to control the X/Z linear axes, high-speed grinding and dressing spindles (60,000 and 54,000 rev/min, respectively) and an automatic load/unload device.

Also, the original design of the machine incorporated size gauging and control.

The older CNC was built in the 1980s, specifically designed for the operational parameters of the grinder and had adequate power and flexibility for its time.

With internal dressing and size control functionality, it had performed adequately at Eaton for many years.

As with all controls, however, it eventually became more difficult to maintain and downtime became an issue for Eaton engineers.

After careful examination of the available controls, as well as the main frame and other mechanical components onboard, the decision was made to retrofit for improved efficiency and on-pace production.

Eaton and Ex-Cell-O (Sterling Heights, Michigan, USA) collaborated on this retrofit project.

They approached the task from a joint venture perspective, in the sense that Ex-Cell-O would manage the controls integration, machine software, interface design, electrical design and implementation of the new system, while Eaton would manage the mechanical aspects of the project.

Eaton would furnish most of the major new components that were already inventories, i.e, those not associated with the control system.

These included relays, switches, terminals and other items that would be reused from the original design, where possible.

The original electrical cabinets would also be reused, it was decided.

Since Siemens, the CNC supplier in Elk Grove Village, Illinois, no longer made a dedicated control for the grinder, a suitable CNC was selected from the current standard line of Siemens product.

The Sinumerik 810D CNC was chosen for the following reasons, as determined by Eaton and Ex-Cell-O engineers: * Compact design - drives and controls are in the same package, resulting in a considerable space savings.

* Digital axis drives - digital drives and absolute encoders minimized hardware and had definitive size advantages for the application.

* HMI interface - compact design of the CNC control interface kept the control console in the same package.

* Custom cycles - Siemens cycle programming eliminated some programming of grinding cycles.

* Imbedded PLC - powerful Siemens Step 7 imbedded PLC controller further enhanced the HMI protocol.

The original Heald grinder controls console required some redesign, as the Siemens Sinumerik 810D control panels are slightly wider than the original System 3.

However, the redesign was achieved, with the capability of mounting to the existing pendant support art on the machine.

The PLC interface was accomplished with Step 7 PLC logic with separate I/O Siemens hardware that provided a more compact design and easily interfaced with the existing I/O terminal connectors.

The Sinumerik 810D is a compact, PC-based control that is used for simple to medium-range CNC applications.

It features an integrated NC, PLC and is capable of handling up to six axes and two spindles.

SIMATIC PLC consists of standard hardware and software components that can be individually tailored to the task at hand.

It is the standard automation system for controlling the widest variety of machines and plants.

The existing program format was used to maintain the operator compatibility with the old programs.

The old programs were approximately 75% transportable with modifications implemented to those areas that required new functionality.

This minimized operator impact with new equipment since the operator controls and the program parameters were basically the same as the old equipment.

Special operator interface screens were designed to match the original parameter values, reducing the need for extensive training of the operator interface system.

Fault and Operator Messages were programmed to minimize downtime and give as much information as possible to the operator and maintenance personnel.

Eaton engineers Rick Gentry and Jim Guess have reported over 11% increases in the overall productivity of the Heald grinder, with the additional advantages of improved throughput and enhanced accuracy since the retrofit.

The retrofit project at Eaton required approximately six weeks to implement and obtain customer approval.

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In early 2005 CNC Design performed a retrofit on a Pfauter Kapp PE1000G gear grinder at David Brown Gear Industries’ Woolongong plant. The heat treatment process used to harden gears and pinions distorts them slightly, so before being fitted to a gearbox these workpieces must be ground to eliminate this distortion. The Pfauter Kapp grinding machine, originally built in 1988 performs this critical final step in the production process.

However the hardware and software used on the machine was becoming obsolete and hard to maintain while the user interface was difficult to learn and inflexible.

The retrofit involved the installation of Siemens 1FT6 digital servo motors to all feed axes.

These motors are controlled by Simodrive 611D digital drives which allow the use of feedforward control.

This provides extremely stiff control and fast machine response which is evident in the smooth surface finish on the gear teeth being ground.

The existing spindle motor was retained and connected to a new 611U drive.

The drives are controlled by a Sinumerik 840D CNC.

This is the only product on the market offering integrated safety features.

Sinumerik Safety Integrated is now responsible for monitoring the working space and ensuring the safety of the operator during workpiece set-up and while checking results.

Safe Standstill monitoring, Safe Speeds and Safe External Stops are implemented to create maximum operator safety at all times.

A new user interface was developed in consultation with the machine operators to allow flexible and intuitive control of the grinding process.

The interface runs on a PCU50 control panel which allows grinding and setup data to be saved to the internal hard disk.

Not only did the upgrade provide an easy to understand and intuitive interface, it also allowed greater flexibility during the grinding process.

Any further machine upgrades or diagnosis are also made easier by incorporating a modem which allows secure remote access to the machine software.

The entire commissioning process, including the rewiring of the entire machine, the refurbishment of all ancillary systems, tuning of all axes and the testing of all grinding cycles, was performed in a six week period of down-time.

Full production was able to begin immediately after this commissioning period.

Reductions in grinding time of up to 40% have been experienced on the refurbished machine.

And importantly, operator interaction has been reduced, increasing efficiency and allowing the operators more time to perform other tasks.

Overall, both management and operators at the David Brown plant are extremely happy with the result of the project.

Not only have productivity and usability been improved, but the future viability of the Pfauter Kapp is assured at a fraction of the price of a new machine