Solid Works” Software permits 3-D dimensional viewing...plus, clearer definition of work holding products and work areas.

Royal’s engineering staff can now communicate with 3-D models in most formats and have the ability to do basic finite element analysis. Also, the new software packages provide the capability to interface engineering 3-D models to the manufacturing area for the developing of machine programs.

In making the announcement, Guy Byrne, General Manager, stated, “These new upgrades enhance Royal’s position today and in the future as a leader in the manufacturing of work holding products. It is imperative that in today’s competitive market we provide our manufacturing facilities with the best state of the art equipment and programming resources available. In turn, our customers reap the rewards of our ability to reduce costs and still produce superior products.”
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Founded in 1956, Royal Machine & Tool Corporation is ISO9001:2008 & AS9100 Rev. “B” Certified and serves the world’s leading industries from its Berlin, CT corporate offices and manufacturing facility representing over 40,000 square feet including state-of-the-art CNC machine tools. All services and products are performed/produced in the USA and include the designing and building of custom and standard work holding devices from simple manual fixtures to sophisticated hydraulic fixtures with multiple faces. Custom and standard chucks of all types for rotating and non-rotating applications are also designed and built by Royal Machine &Tool…as well as a complete range of Contract Machining options/services from single prototype machining to high volume production requirements.

The ISO provides quality management system standards/guidelines aimed in assisting organizations to achieve customer satisfaction and continual improvement. Certificates to organizations in over 160 countries have been issued by ISO.

The two recertifications in accordance with the requirements of ASI9104A are applicable to Royal Machine & Tool’s design, manufacture, assembly and service of commercial and aerospace products.

In making the announcement, Royal President, Richard Ruscio stated, “Since 2003, we have been especially proud of our being certified in accordance with ISO and ASI requirements. Royal’s new recertification confirms the major commitment by our management in continually providing the necessary quality products and contract machining services required to meet our customers’ work holding needs.”

Founded in 1956, Royal Machine & Tool Corporation serves the world’s leading industries from its Berlin, CT corporate offices and manufacturing facility representing over 40,000 square feet including state-of-the-art CNC machine tools. All services and products are performed/produced in the USA and include the designing and building of custom and standard work holding devices from simple manual fixtures to sophisticated hydraulic fixtures with multiple faces. Custom and standard chucks of all types for rotating and non-rotating applications are also designed and built by Royal Machine &Tool …as well as a complete range of Contract Machining options / services from single prototype machining to high volume production requirements.

A typical Robot System integrated with a Machining Center…complete with safety fencing, monitoring and part queuing stations.

Like any new process, robots were introduced with many skeptics. Non-believers thought the human process could not be replaced…and that robots were too cumbersome to do the job at hand. Also, many felt threatened by the use of robots as they were perceived as causing the elimination of someone’s job and not improving the overall workplace performance.

Over time, the use of robotics has expanded as manufacturers realized the benefits that they can bring to manufacturing processes. Today robots are commonplace in the assembly of automobiles and many of their components. The benefits of robots include the ability to work 24/7, reduced labor costs, repeatability of the process, reduction of accidents and scrap.

Presently, the use of robots is finding itself in operating rooms doing surgical procedures where accuracy is a must. In manufacturing, their use has expanded beyond assembly, to the machining operations where they are used for loading and unloading parts from lathes and machining centers. This has brought change and challenges to the way parts are fixtured and processed.

With the use of robotics comes different design requirements of the fixturing.

Fixtures now have to provide enough clearance to allow robot arms to manipulate the parts into the work nest and provide better chip evacuation. In addition, fixtures have to provide the ability to retain the parts in a free state prior to clamping and unclamping. Lastly, fixtures must have the capability of knowing when a part is not sitting properly in the work nest.

A Robot loading parts on to the Hydraulic Fixture within the work area of the Machining Center.

To begin the process of the robot with the workholding fixture, the loading surface has to be designed with better chip evacuation and to be clean of any foreign material that would not allow the part to seat properly in the work nest. This may require an air or coolant source to remove chips or debris on the work area. In most cases the area is flooded with a coolant flush from the machine and then an air blast from the robot arm. Next the robot has to have the ability to load the part in the nest without the part falling out before it is being clamped. This requires a provision for some type of preload mechanism to hold the part in position for the clamping. This may be simple spring clips or a spring loaded low pressure clamp mechanism.

Once the part is now in the preliminary load on the work nest, the final clamping of the part takes place with the robot retracted. However, confirmation of the part being located and properly clamped is required prior to the machining process. This is usually done with air sensing on the Locator Pads and/or Part Clamps. Basically, a low air pressure is forced through a small hole in the locator or clamp. If the part is located properly (thus blocking the air passage), it will signal an increase in air pressure which, in turn, signals to the machine control that the part is located properly. If the part is not seating properly, the air pressure will drop off
and will signal an error in the process.

Adding to the intricacy of the fixture…

Providing the preliminary part locators and part sensing into the fixture design adds to the intricacy of the fixture. The hydraulic and air lines are normally internal to the base plates and work nests. This allows a cleaner fixture with better access and chip disposal. Hard piping is cheaper, but in the long run, takes up more space and tends to collect chips, and is susceptible to damage and leaks.

Once the machining is complete, the unload/load sequence of the robot is ready to complete the cycle. First the hydraulic clamping has to be disengaged allowing the parts to sit ready for unload. The machine control then initiates the coolant flush and the robot takes over the operation, grabbing each part and going through the load/unload sequence. This is a continued safe repeatable motion and timed process.

Today, as greater flexibility and quick changeover become the requirements to be competitive in manufacturing, the connection between Robots and the Fixtures will become much more sophisticated and an intricate part of the fixture design.Eventually, it is not that farfetched that a robot may become the fixture as well as the part handler.

Photos courtesy of Makino Production Machinery Group.

Special Automatic Index Chuck.

When processing a workholding job (and to optimize the process), there are a number of considerations in selecting the appropriate chuck. In most cases the least consideration is the way the chuck holds a part.

Initially, you must first look at the work piece you want to hold. A round piece of bar stock is the most simple of geometrics to work with. However, not all parts come from bar stock…some come as castings or forgings with non-uniform shapes. And this is where the selection process requires some thought because of the wide variety of chucks and options available.

The most common chucks are Standard Two or Three Jaw Chuck and Collet Chuck. More intricate shaped parts may require an Anvil Type One Jaw Chuck or a Four or Six Jaw Chuck. Listed below are the various basic chuck designs and where they are best suited. Each design provides various options…but, for now here are the basic applications.

• One Jaw Chuck – used for parts having a qualified side surface as a datum.
  

  Multiple Spindle Chucks.

• Two Jaw Chuck – used mostly on square shaped parts.
• Three Jaw Chuck – used mostly for round shaped parts.
• Four Jaw Chuck – used to stabilize the grip on square parts.
• Six Jaw Chuck – applied to thin-walled parts requiring wrap around clamping to avoid distortion.
• Collet Chuck – used with parts requiring wrap around clamping while not marking the part…yet still maintaining close concentricity requirements.
• Index Chuck – used for parts with various centerlines as reference.
• Diaphragm Chuck – used with parts requiring optimal grip while machining plus critical part tolerance while not allowing distortion and markings.

It would be great to have all of the above chucks available in your tool room arsenal. However, that is never the case.

To select the most appropriate chuck, you must first review the following categories and determine the best method of chucking based on each of these areas: The Workpiece, Machine, Production, and Process.

Let’s now take a more in-depth look into each of these categories.

WORKPIECE

Looking at the work piece configuration, we have to find the best way to hold the part. This is best determined by the tolerances and operations required to produce the workpiece. It would be ideal to be able to machine the part complete in a single clamping. In many instances this is possible with the proper choice of chuck because we all know that the objective is always to handle the part as little as possible. Looking at the variety of chuck styles available will help in making the right decision. Not all parts are symmetrical. Some have a flange or outrigger which is a concern with speed and balance. This situation may call for the proper means to counterbalance the part or to reduce the speed of the process.

Sometimes parts are thin-walled and will distort when clamped with a standard 3-Jaw Chuck. A Collet or Diaphragm chuck may be the answer. Or, it may just require a reduced clamping pressure to allow it to secure the part, but not distort the part. In most cases, where distortion occurs, it is because of extreme clamping pressure. The first concern is that the grip pressure be substantial to hold the part in a safe and secure fashion. Once we review the work piece, we can now proceed to determine the machine tool.

MACHINE

There are many considerations to review in selecting the machine. Unfortunately, the ideal situation would be to have any machine and chuck available. We all know this is never the case. If your part can fit a machine with the right capabilities, that is ideal. However, it may be that you are restricted to a certain machine. Now you have to make sure the chuck mounting is compatible with the machine. What is the machine’s speed and horsepower? Is there sufficient rpm to obtain the surface footage required? Does the machine cylinder have the necessary pressure for the chuck and is there adequate cylinder stroke to actuate the chuck? Finally, is there enough swing clearance for the chuck, part and the tooling to process the part? The envelope of the machine may also restrict your capabilities.

Modifications may have to be made to the machine if your application calls for special fixturing such as an Index Chuck or a chuck with retractable locators. In most cases, when looking at Index Chucks, they require a separate hydraulic unit, double-acting cylinders, cylinder adapter, and tubing in lieu of a standard cylinder and drawbar or drawtube. Therefore,
in some cases you may have to make changes to the machine. For high production applications these type of changes are usually permanent
and require another area to be considered.

PRODUCTION

In just making a single piece, it is most appropriate to use a Manual Operated Chuck and Universal Jaws to clamp the part. Cycle time is not an issue because it is only a single workpiece. The part can be pecked-away-at without concern for any load from clamping or tool pressure. Tolerance and finish are wide open. This scenario plays out every day in many small shops.

High volume production of precision parts may require it to run unmanned, with clamp/unclamp detection as well as pressure monitoring and sensing of proper part location. This is only for the chucking phase…and may also require Automatic Load/Unload, automatic tool offsetting and breakage.

PROCESSING

Once the process is determined, the clamping method can be checked for locating the part appropriately and allowing sufficient clearance for the tooling, coolant flow and chip evacuation. The process indicates the datums for the dimensions being machined. In turn, this determines how the part is located and gripped. Now look at the tools and their tool path to make certain clearances are available. Clearances can be made as long as the integrity in clamping the part is not breached. This also holds true when allowing room for chip evacuation or coolant.

In many cases the part can not be completely machined in a single clamping. When doing the finish operation, the part may have to be oriented more precisely or in a different fashion. For example, a part may be held in a 3-Jaw Chuck for the roughing operations to remove the material with heavy depths of cut. Where roundness or concentricity are vital for the finish operation, a Collet Chuck may be the best option.

Review of each of these four categories should assist in determining the appropriate Chuck and Top Tooling to produce a quality part in a timely fashion with safety always in mind.

High Speed Anvil Type Index Chuck.

There are still many chucks manufactured fifty years ago that are still working today in making quality parts.

However, with the demand for higher speeds and feeds, improved surface finishes and tighter tolerances has come changes in manufacturing. CNC Controlled Machines replaced Manual Lathes. The tooling industry developed Coated Carbides to attain the higher demanded speeds and feeds. In order to reach these goals, chuck manufacturers have had to respond with workholding devices that could meet the situation and its ever-increasing demands.

High Speed Counter-centrifugal Chucks, Index Chucks, Chucks with shifting Centers, Compensating Chucks with Collets or Mandrels are becoming the norm on lathes. As the lathes take on the look and capability of a “Universal Machine”, the situation requires versatility in the way a part is gripped.

To meet today’s demands, workholding manufacturers have met a whole new challenge.

Originally, production requirements were high volume. The situation allowed multiple operations over a number of machines. Each machine was somewhat specialized in the sense that achieving changeover required much downtime. Therefore, when a changeover was required, it was limited so as to not disturb the production. This, in turn, caused machines not to work efficiently at the available speeds or feeds because the tools were “OK” or the chucks could hold a variety of parts efficiently.

These lathes not only have the capability to turn parts at high speeds and feeds with better accuracy and repeatability, they also have the capability for drive tools, milling capabilities, automatic gaging, tool offsetting, automatic load/ unload, spindle positioning and backworking. All these options allow for many parts to be completed in a single operation, with one setup and one clamping.

Now, let’s look how all these demands and objectives can be accomplished by going through the thought process and determining the best possible method to hold our part.

The obvious goal is to make your product in a single setup…in the fastest time…at the least cost… and of the best quality.

It sounds simple. However, that is one loaded objective. In most situations, all the ingredients are not available. The machine may not have all the needed capabilities. The costs may not be justifiable, or the required quantities may determine the process. The variables go on and on.

Initially, the chuck size has to be established. You want to make sure the part will fit safely and securely within the chuck envelope. Like everything else, there may be exceptions. The part may not always be round, or may have an extended arm, which will require a counterbalance.

Next, the type of chuck has to be determined. A common 3-Jaw Chuck is appropriate for most turning applications. However, if the part is rectangular in shape, a 2-Jaw Chuck may suit the part better for gripping. Another option may be a Collet Chuck or Mandel to maintain concentricity requirements between operations.

Review the part print and the tolerance requirements to define the process method(s) and to obtain your objective…a consistent quality part in the least time. To accomplish this goal is to establish the process suited to the dimensional and finish requirements of the part. Datums are established for a reason. Know where they are and use them accordingly in your setup.

Production will dictate the process and tooling more than anything. If you have a job of major volume, you will want a power actuated fixture that allows the ease and quickness to load/unload in the shortest possible time. On the hand, if you are going to make only one or two pieces, you would use a manual chuck with top tooling capable of holding the part at the speeds and feeds necessary to cut the part. However, this is probably not the most efficient method.

Selecting the proper workholding method is just as critical as determining the correct cutting tools, speeds & feeds, and process. Like the aforementioned items, there are references, recommendations and many vendors with expertise to assist in the selection process. It would be to your benefit to use these knowledgeable and experienced resources to guide you.

Before: typical Defective Chuck.

Answering the question…”How do you decide which is correct for your situation?”

There are still many chucks manufactured fifty years ago that are still working today and making quality parts. However, when (or if) a chuck(s) begins to perform improperly, you must make an important decision as to either repair, recondition or replace the defective unit. And there are many considerations to evaluate in making that decision.

Obviously, safety considerations are first and foremost in determining the overall results you are looking to achieve. Then, you must decide whether the chuck has to operate for a short period of time or for a long period of trouble-free use. And, most importantly, how will the cost difference of each of the three “R’s” effect your decision?

Now, let’s look at your reasons to consider repairing, reconditioning or replacing the chuck:

1. Does the chuck visibly appear to be worn?

2. Has an accident broken something in the chuck?

3. Has the chuck begun to lose its gripping force or its accuracy?

4. Is the Chuck design incapable of holding a part to meet your part process and tolerances?

If the answer to any of these questions is “YES”, then you should consider the three “R’s”.

REPAIRING

Usually, this is the least expensive service and the quickest to get you back in production. If there is a broken master jaw or a broken jaw activator caused by an accident, then replacing the broken part and cleaning up some damaged surfaces can make the chuck serviceable at little expense. However, an exception to this service is when the broken part is a special part. Then it may have to be reverse engineered and manufactured which is more time consuming and costly.

The repairing procedure provides a very serviceable chuck… returned to its original condition prior to breaking. However, the repaired chuck is still a somewhat worn chuck with a warranty only on the replaced parts and workmanship. A final consideration is that replacement parts may not have the same fit with worn parts which, in turn, may not provide the best situation
for holding parts.

RECONDITIONING

This is the midrange expense of the three “Rs” and is recommended when the cost of reconditioning is 60% or less of the price of purchasing a new chuck A correctly maintained and lubricated power chuck will usually age gracefully and will only show wear by loss of accuracy and/or gripping force. When sent in for an examination and/or testing, all the major wear surfaces will be inspected. If found to be worn, they will require rebuilding of one form or another.

The forms for building up worn surfaces are either chrome plating or welding. After the worn surfaces are built-up and the parts are carefully checked for any possible cracks, the new surfaces are ground to like-new chuck tolerances. Master jaws are also qualified to like-new chuck tolerances.

After: Reconditioned Chuck. After: Reconditioned Chuck

Once an original chuck has been reconditioned to new chuck standards, it usually has a one year warranty (the same as a new chuck)…and for most situations is equal to new chucks
in reliability.

Reconditioning usually can be done in half the time it takes to have a new chuck built. It may be such that a part has to be replaced, welded or plated. However, you have most of the chuck already completed.

It is important to note that replacement chucks still retain the old chucks’ design with any problems and/or deficiencies inherent to the old design. Any desired changes usually require replacement.

REPLACING

Quite often the cost of reconditioning exceeds 60% of the cost of a new chuck or it’s simply time to update and replace with a new design chuck.

The new chuck will have all the advantages of the latest designs and materials plus many times your operations have changed and you require redesigns to improve performance.

In addition to receiving a full one year factory warranty, possible considerations for selecting new chucks are:

1. The need to operate chucks at a higher RPM.

Today’s selection of coated carbide tooling requires much higher speeds and feeds than before. Current designs take high speed in to consideration, using counterweights and counter centrifugal mechanisms.

2. The additional travel required in master jaw strokes.

The usual stroke of a standard chuck is 3/8″ per jaw which in most cases is substantial. However, with the long stroke chucks this can be up to 1″ per jaw. This permits gripping parts where a flange may have restricted gripping only a certain area which may not be the ideal situation. Also, the longer stroke will allow the gripping of more part diameters with the same set of jaws…thus reducing setup time. With automation, the long stroke chuck allows part to be loaded more easily and also permits chips to escape more easily.

3. The ability to mount locators on chuck facings.

Newer chuck models allow Locators or Locator Bungs to be mounted on the face of the chuck which provides a stationary repeatable flat surface for the part to locate. Usually the locating face is on the moving top jaw and may yaw when clamping. Thus giving inconsistency from part to part.

4. The adding of new options such as Part Sensing, Chip Blasting, and Automation.

Today, in order to stay competitive, many companies have to run “Lights Out” with robots or automation which requires a great deal of sophistication throughout the whole process, …including the chucking. Monitoring the chucks actions is critical to preventing a problem which would shut down the process. Feeding air pressure thru the locating surface is a common way, to detect if a part is not located properly. A drop in air pressure signals that the part is not seated properly, thus allowing the air to escape. Air may also be fed thru the the spindle to blow off chips from the mounting surface and part. Today, sensors can be
used to indicate clamp/unclamp, part location, and clamping pressures.

Making the right decision is critical and it would be beneficial to ask the assistance of a knowledgeable vendor in guiding you to make this most important decision.

Naturally, the final decision is yours and must be based on what is functionally and financially best for your situation…REPAIRING, RECONDITIONING, REPLACING…they all have their place.