EDITED BY ANGELA OSBORNE   Managing Editor, Production Machining

Learn More at ​Workholding Fixture SystemsGrip Pallets

Blue Photon’s grippers are inserted into new external inserts, designed specifically for the Grip Pallets. The external inserts are available for use with small, medium and large grippers. The new inserts allow for simple installation of the grippers at the required height for maximum holding power.

The 150-mm square pallet is available in aluminum and steel with a 52-mm pattern for a quick change receiver that will hold up to nine grippers. The 225-mm square pallet is available in aluminum and steel with a 96-mm pattern for a quick change receiver that will hold up to 21 grippers. The 300-mm square pallet is available in aluminum with a 96-mm pattern for a quick change receiver that will hold up to 33 grippers.
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Each Grip Pallet includes two handles with multiple color choices and four spacers, with a 25.4-mm standoff that allows for the recommended nominal of 1-mm joint thickness between gripper and part.

​Optional clamp studs are available for both 52 mm and 96 mm patterns for 5th axis, Jergens, Lang and Mate systems. Part can be removed with a ¼ turn twist of the gripper or hot-water soak. Residual adhesive is removed by using a handheld steamer or a hot-water soak and a light peeling action.

Check out these details and more from the IMTS video below.

It's that time of year for IMTS!

​Here's a preview of some of the products that are going to be featured during the International Manufacturing Technology Show September 12-17.  You can see all of these new products and talk to the manufacturers in the Tooling & Workholding Systems Pavilion in the West Building Level 3. 

Supermini Set. Horn USA is featuring the Supermini tool holder system with face clamping as a set, in response to customer requests for different tooling system heights. With this holder variant, clamping is not carried out via the lateral surface of the cutting insert but via a clamping wedge on the face. This results in a greater holding force on the insert and thus high rigidity of the entire system. This increases repeatability when changing the insert and provides better utilization of the available space. This is a big time saver on Swiss-type lathes, as the user can change the cutting insert without removing the tool holder.

New carbide grades for system DAH8 - Horn USA is expanding its range of carbide grades for its DAH milling system to enable its use for machining a wider range of materials. The new grades SC6A and IG6B complement the tool system for high-feed milling. The SC6A grade is suitable for machining the ISO M material group, as well as ISO S materials as a secondary application. Horn has developed the IG6B grade for machining the ISO P group, while it is also suitable as a multipurpose grade for other material groups.

If you would like to learn more about any of these products or to see a demonstration, get in contact with us and we'll set up some time with you to visit your shop!

Edited by JENNY RUSH, Senior Managing Editor, Modern Machine Shop

Blue Photon’s grippers are inserted into new external inserts, designed specifically for the Grip Pallets. The external inserts are available for use with small, medium and large grippers. The new inserts allow for simple installation of the grippers at the required height for maximum holding power.

The 150-mm square pallet is available in aluminum and steel with a 52-mm pattern for a quick change receiver that will hold up to nine grippers. The 225-mm square pallet is available in aluminum and steel with a 96-mm pattern for a quick change receiver that will hold up to 21 grippers. The 300-mm square pallet is available in aluminum with a 96-mm pattern for a quick change receiver that will hold up to 33 grippers.
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Each Grip Pallet includes two handles with multiple color choices and four spacers, with a 25.4-mm standoff that allows for the recommended nominal of 1-mm joint thickness between gripper and part.

​Optional clamp studs are available for both 52 mm and 96 mm patterns for 5th axis, Jergens, Lang and Mate systems. Part can be removed with a ¼ turn twist of the gripper or hot-water soak. Residual adhesive is removed by using a handheld steamer or a hot-water soak and a light peeling action. 

Watch the full episode covering workholding on Swarf Talk HERE
Swarf and Chips is sponsored by Intoco Special Steels and Alloys.
Courtesy of MTD CNC Media and Swarf and Chips.

Blue Photon manufactures a patented photo-activated adhesive workholding system in the U.S.

​They also offer fixture design and engineering for milling, turning, grinding, electrical discharge machining (EDM), 3D printing/additive manufacturing, laser, inspection and assembly applications for the aerospace, medical, optical, and robotic industries.

You can view or download the catalog below.

​For a more in-depth visual of how Blue Photon’s UV workholding technology is a solution to your workholding needs, check out their videos HERE. ​

​New optical workholding adhesives provide alternate solutions
to the challenges of traditional holding methods
written by Dan Billings & Shannon Osborn, Blue Photon 

New processes 

With new adhesives, traditional holding processes change. First, a thick layer of adhesive is applied between the part and holding device. Grippers are inserted into a fixture and can serve as the interface between the workpiece and holding device if needed. The workpiece is then secured to the grippers with the workholding adhesive, which is cured with UV light transmitted through the core of the gripper. The average tensile holding power of the gripper is between 200 and 605 lbs per adhesive joint and based on the size of the gripper selected. 

When the workpiece is loaded, UV light is either passed through the grippers or the workpiece material for 60 seconds to cure the workholding adhesive. Once cured, the workpiece is held in place securely, which allows for aggressive processing. The parts can then be removed from the holding device by hot water soak with a temperature between 170 and 200 ºF. The high temperature eliminates the need for toxic solvents and allows for faster release of the adhesive. Typical debonding time generally runs 2 to 5 minutes. Residual adhesive is easily removed by applying pressurized steam or hot water spray in conjunction with a gentle peeling action (Figure 4).

This article is about Blue Photon Technology and Workholding Systems LLC  and how Post Processing; 3D printing presents challenges in workholding for finish machining.
Written by Mark Kirby AM Business Manager, Renishaw Canada

Metal 3D printing can enable rapid, low cost iterations of new medical devices, since no tooling costs are involved. All devices need testing to uncover problems and develop solutions—allowing the product shape to change “for free” is a powerful advantage with Additive Manufacturing (AM). Other benefits flowing from AM besides enabling more complex geometry are improved accuracy with no component tolerance stack up, and a simplified supply chain with reduced part count.

Plastic printed jaws are often a good first option, as they are cheap to manufacture—typically in just a few hours on a desktop printer, and can conform to complex geometries (although the design of the jaws can be more time consuming than a simple Boolean subtraction of the component from the plastic). When the design changes after product testing it is easy to print a new set of jaws.
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The main disadvantage of plastic jaws is that they will often distort the component as they are tightened. Although the jaws hold the part rigidly for machining, when the component is released from the fixture any machined bores may no longer be perfectly round, and true positions of features will have moved slightly as the component relaxes back into its unloaded shape.

The tracker body was monolithically printed in titanium alloy  Ti6-4, stress relieved and then cut from the build plate ready for finish machining of the kinematic mount and the four posts that hold the optical reflector globes.
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A plastic set of jaws was designed to clamp the part while leaving the machining areas exposed. Although the plastic jaws clamp the part rigidly, they never clamp the part repeatably, so the exact position of the part must be found using a machine probe and best fitting software such as NC-PerfectPart, from Metrology Software Products Ltd. (MSP). Originally developed for machining of high value aerospace and Formula 1 composite structures, this software is perfectly suited to the challenge of precisely locating an organic-shaped AM part with no obvious datum features.

Points are selected on the component in the CAD environment and the deviations from nominal positions are measured by the probe on the CNC machine. The NC-PerfectPart software then creates a best fit alignment that is a 6-axis coordinate transformation—both translation and rotation. This coordinate shift is automatically recalled into the machine controller before CNC programs are executed.

Unfortunately, the hip tracker component flexed imperceptibly when the plastic jaws were clamped, resulting in true position errors greater than 0.3mm on the machined posts. While the component had been optimized for handling loads during surgery, it had not been designed to resist machining forces.
In order to machine the part accurately it was essential not to bend it with mechanical clamping, but at the same time it was equally important to add rigidity.

The solution was to use Blue Photon’s UV activated adhesive and grippers. By gluing the part onto four gripper posts (that transmit UV light to cure the glue in approximately 90 seconds) the hip tracker was held firmly but still in the free state.

An aluminum block was machined to hold the four gripper posts in the correct positions for the tracker body. Initial machining was successful on the three posts directly bonded to the grippers, but one post was cantilevered above the gripper and vibrated during machining. A plastic support block was printed to hold this post and eliminated this problem. By cradling the part, the support block also allowed for more accurate positioning of the tracker prior to the glue being cured. The glue thickness is optimally around 1mm, and after machining the part and fixture can be separated by simply immersing the assembly in near boiling water for a few minutes, and then peeling apart.

The only disadvantage of using the glue grippers appeared to be the extra work to design and machine the gripper fixture. However, on a subsequent project for an industrial impeller Renishaw used plastic printing to produce the gripper fixture instead of machining. This proved that the manufacture of a robust, custom workholding solution can be reduced to an overnight desktop print.

The procedure for a patient specific medical device like a cranial plate would be as follows. The number and placement of the grippers would be determined by the manufacturing engineer. “Preserve” regions would then be defined around each gripper as a cylindrical “bushing” with obstacle clearance regions extruded axially above and below each gripper to allow for insertion and captive nut placement.

​The cranial plate is also defined as an obstacle that must be avoided. A preserve ring would be defined, and constrained, to enable the completed fixture to be held in a chuck. Loads are added to the gripper bushing preserve regions to represent machining forces that must be resisted. The software can then solve the structural connection of all the parts for maximum stiffness.

One of the barriers to adoption of patient specific solutions is the high design cost typically involved. Using generative design coupled with plastic printing is an innovative solution that largely automates the workholding process with Blue Photon’s adhesive grippers.

From: Aerospace Manufacturing Magazine
by : Mike Richardson, September 2018

Mike Richardson meets JJ Churchill’s executive chairman, Andrew Churchill to hear about the latest developments of its aerofoil blade machining techniques with the help of a new workholding concept called Blue Photon.

A first-tier expert in the production of gas turbine blades from forgings, castings and solid billet, JJ Churchill says it has halved machining operations on specific critical parts using Blue Photon technology – which is marketed in the UK and Europe by NCMT.

Blue Photon technology enables engineers to realise benefits not possible previously with mechanical fixtures alone. JJ Churchill has utilised the Blue Photon technology in an innovative way to deliver huge productivity benefits for its customers.

Here, the technology is applied to a titanium aluminide aerofoil blade component which is an extremely difficult material to fixture and machine. Blue Photon fixes the component to the workholding fixture with an adhesive, which when cured under UV light, is strong enough for the most rigorous machining techniques including 5‐axis CNC. The process is a replacement for encapsulation, providing reduced fixture complexity.

“You can often see real value by looking outside your sector at the typical technologies used on the products you make instead of just within your supply chain – it’s what I call horizontal innovation,” begins JJ Churchill’s executive chairman, Andrew Churchill. “Workholding is a classic example, i.e. how well a company can drive its process and quality performance is directly connected to how well it can repeatedly, robustly and rigidly hold the workpiece it is machining, otherwise it will never achieve a process-capable machining solution.

“We’re very interested in how we can best hold aerofoil blades. They possess a beautiful, sinuous shape, but are very difficult to clamp efficiently. Conventionally, a blade is secured using hard-point fixturing and a clamping solution which is expensive to make and has numerous drawbacks. Alternatively, the blade can be encapsulated by being placed in a mould and adding a low melting point metal or resin alloy, which takes it from a sinuous aerofoil shape to a solid block. This is expensive, and the design of the encapsulation fixturing is complex because it requires cooling water channels and electrical contacts, as well as moving parts and a decontamination at the end of the process.”

"A technique derived from prismatic machining, when exposed to UV light, the plastic polymer cross-links and sets. We pick up the datum points on the blade forging which allows us to use Blue Photon plastic glue to adhere a new set of datum points through a metal fixture with sapphire waveguides onto the blade. And because it’s a square shape, it can be clamped much more efficiently. After blade machining, the glued-on metal datum block is simply removed and the finished blade product is washed off with warm water. It’s a radical approach – we’ve taken Blue Photon’s licensee, NCMT’s intellectual property and developed the know-how for aerofoil manufacturing applications.

“In terms of benefits, we no longer need to design a complex and expensive encapsulation fixture, we can machine more faces of the blade, we’ve removed the slow-melting alloy encapsulation and part decontamination processes. Combined with other novel manufacturing processes such as additive manufacturing removes substantial amounts of lead-time from the new product introduction (NPI) process. Typically, we remove a quarter of the lead-time and about a quarter of the cost of NPI on a blade using the combination of Blue Photon and additive manufacture of coordinate measuring machine (CMM) fixtures. It’s incredibly powerful because if you can respond rapidly to NPI, you stand a better chance of getting the volume work of an aero engine programme.”

Once the blade root and tip have been machined, the workpiece is transferred to one of JJ Churchill’s Starrag LX051 5‐axis machining centres. The workpiece is held in specifically‐developed fixturing for the fast and effective complete machining of the aerofoil from forged blanks that are, at most, 5mm oversize.

“We’ve had Starrag machines for well over ten years, but we work with a relatively small number of top-notch, global machine tool suppliers. It’s really important to develop a deep relationship with those suppliers. We will visit them at least once a year to get involved with their R&D activities, so that we understand what is coming through as potential opportunities. We could wait and see what the large OEMs are pushing in terms of technologies – or we can get aggressively involved, help them solve some of their problems and get the opportunity to be partner with them on some of the technical developments going forward. We’ve done this very successfully in a number of areas.

“We usually get two years of advance notice of winning volume production contracts on any given programme. Volume production means building a bespoke cell, which requires investment and poses the question: in terms of single-piece flow, what is the best technology to drive global cost-competitiveness and process capability for this specific customer? We have a shortlist of potential machine tool suppliers where we can form a partnership, sign a non-disclosure agreement and put the supplier alongside our engineers to develop a proposal. This can form the basis of a long-term contract. We will then build the production cell and deploy it.”

ll this talk of the potential volume production hints at product process capability and robust process stability. How much importance does Churchill place on Industry 4.0, automation and the advent of ‘smart tools’ in general?

"We produce gas turbine blades for engines that will be in service for decades. If we’re still making them the same way whilst competitor economies like Germany continue to drive the application of Big Data and Industry 4.0 as a productivity advantage, then the UK will eventually lose out.

“More in the ‘here and now’ is automation. The use of robotics in a high labour cost economy will have its place – and the UK is a high labour cost economy. We’re looking at how we can link together our VIPER grinding centres and CMMs and automate them. The first step is a ‘pick and place’ robot: a robot arm and end-effector selects a turbine casting, places it on the grinding machine, removes it on completion and places it on the CMM. This offers some advantages but it’s not really earth-shattering.
“The real value is gained with closed-loop adaptive machining. The robot does what I’ve just described, but when it gets to the CMM, the CMM talks to both it and the grinding machine and says for example, ‘this is a nonconforming blade, there is a material-on condition, so we need to re-program and postprocess back to the grinder and remove more material from these features’. Completely without human intervention, this closed-loop output from the CMM is fed back to the CNC grinder, regrinds that blade and re-measures it to establish that it now conforms.

“This is adaptive machining. Even more exciting is where there are upper and lower feature control limits. If that feature is beginning to drift inside the upper and lower control limits, the operator will either take action or simply wait and see. However, in a closed-loop adaptive environment, if the feature begins to drift, the output from the CMM data linked into the VIPER grinding machine can adjust accordingly to make minute incremental offset changes and nurse it to hit closer to nominal all the time. This is what we will be doing and we’ve already designed a cell which is ready for the robots and designed with closed-loop adaptive machining in mind.”

Churchill then poses a relevant question: what does this mean to employment? After all that has already been discussed, it doesn’t surprise me to hear him say that as a rapidly growing business, JJ Churchill will be re-deploying its employees internally and re-skilling them accordingly.

“Companies will need to accurately plan a growth curve so that they can redeploy their labour. We want to take the experience our workforce has gained over the years and keep it, but retrain and augment it with the kinds of skillsets that will be needed to get the most out of digital manufacturing.

“We will also be looking to ensure our apprentices join us with ‘digital-ready’ skills. We’ll need people with grinding skills and those of being able to interact with robotics and programming, whilst operators with lower skillsets can be employed to ensure the cell is fed with raw material. It will require huge changes in our industry’s skillsets and it’s one that we’re eyes wide open to, but it will be a challenge for our sector as a whole in moving forward.”
www.jjchurchill.com
www.ncmt.co.uk

This article about Blue Photon Technology and Workholding Systems LLC originally appeared in Modern Machine Shop magazine.
Written by Derek Korn

Precision Grinding and Manufacturing uses an atypical means to fixture thin parts that are prone to flexing when conventional workholding clamps are used: adhesive cured by UV light.

Operators must take care not to distort such parts while tightening clamps, otherwise the parts will spring back to their natural state once the clamps are removed after machining.

Vibration can also be an issue for parts like these if they aren’t rigidly fixtured, meaning a quality surface finish might be tough to achieve and cutting parameters might have to be dialed back, extending cycle times. Finding a way to effectively fixture complex, contoured parts can be just as difficult.

Ray Bray says Precision Grinding and Manufacturing (PGM) fought these problems in the past. Mr. Bray is a project engineer for the Rochester, New York, contract shop that specializes in complex, short-run, often repeating work for industries including aerospace, automotive, medical, military, optics, photonics and telecommunications.

Bray says PGM has employed a variety of unconventional methods to more effectively secure relatively thin workpieces for machining over the years, going so far as to use clay, lead and sandbags to supplement conventional mechanical clamps in an effort to minimize vibration.

You won’t find those types of workholding workarounds being applied there today. Instead, the shop uses an advanced, albeit atypical technology that is particularly effective for fixturing flexible parts.

In short, this technology uses adhesive to temporarily bond a workpiece to numerous cylindrical grippers installed in a fixture plate. Once the adhesive is cured via ultraviolet (UV) light, the workpiece is securely held at a known datum location in an undistorted, freestate condition.

After machining, the adhesive bonds between the grippers and workpiece are easily broken and any excess adhesive is removed from the completed part via a quick, steamcleaning wash.

Mr. Bray says that while this workholding technique isn’t appropriate for every job that runs through the shop, it has opened opportunities to win work that, in the past, PGM might not have considered bidding on due to the inherent fixturing challenges. It has also enabled PGM to improve existing fixtures the shop uses for jobs that regularly repeat.

William Hockenberger established PGM in 1967. The shop is now led by his son Mike, who is president and CEO. Business has been good over the years, and PGM has recently completed a 20,000-square-foot facility addition, bringing total floor space to 68,000 square feet.

PGM has a wealth of CNC equipment, including machining centers, turning centers and grinding machines. Milling represents the bulk of the work performed there today, for which the shop uses VMCs with four- and five-axis capability as well as HMCs with pallet pools.

William Hockenberger’s son Todd, PGM’s coporate vice president, explains that because a good portion of that milling work involves thin and complex workpieces, the shop has continuously looked for more effective ways to secure those types of parts for machining.

A few years ago, PGM learned about photo-activated adhesive workholding (PAAW) technology that was developed at Penn State University, which looked to be well-suited for such troublesome parts. PAAW technology was invented by Professor Edward De Meter, who was awarded two patents covering it. In 2012, Professor De Meter and others formed Blue Photon Technology and Workholding Systems LLC to market the technology to industry end users.

Mr. Bray says the fixture design process using the PAAW system is similar to other more conventional fixtures. In many cases, the shop will create a fixture plate with three hard datum points for a part to rest upon so its location is known in space. (Temporary pins can be used to ensure that the part is installed correctly on the fixture plate.)

PAAW grippers are positioned at various locations, and oftentimes a gripper is used at each hard datum point. The number of grippers used largely depends on the size of the part and its geometry. The threaded grippers install in the top of the fixture plate and require a through-hole to enable the UV light to pass up and through the gripper to cure the adhesive.

The photos above demonstrate the process for fixturing and removing a magnesium casting that PGM machines on a four-axis VMC using the PAAW system. With the fixture plate installed on the machine’s rotary table, operator Alan Jedik dabs the top of each pin with a bit of adhesive. He then installs the casting onto the fixture, which rests on the three hard datum points, and inserts the UV light source’s light guide into each of the three grippers located at those datum points. It typically takes 30 seconds for the UV light to cure the adhesive on each gripper. Mr. Jedik rotates the fixture for easier access to the remaining six grippers and cures the adhesive at each of those points. The part program can begin once the table is rotated back to its proper position.

After machining is completed, a T-handle wrench is used to back off each gripper, twisting the element and shearing the adhesive bond with the workpiece. The workpiece can then be taken off the fixture and a subsequent cleaning operation using a portable steam cleaning device is used to remove any cured adhesive that remains on the workpiece. Adhesive must also be scraped off of the tip of each gripper using a metal scale or straightedge before a subsequent workpiece can be fixtured for machining.

The gaps between the workpiece and grippers (thus, the thickness of the adhesive) can range from 0.010 to 0.125 inch depending on the flatness of the part. The uncured adhesive, which is non-toxic, is sufficiently viscous that it won’t run off grippers regardless of orientation. Axial holding force depends on gripper size and can range from 250 to 800 pounds when using Blue Photon’s BlueGrip S1 adhesive.

Grippers are made from hardened, corrosion-resistant stainless steel and have a black oxide finish. For repeat jobs, PGM will commonly leave the fixtures intact with the grippers still installed and store them for later use. Otherwise, the grippers can be removed and installed in other fixtures created for new jobs. The latter is most often the case for PGM, because new work continuously flows through the shop.

PGM has found that the PAAW system can be used in conjunction with conventional clamps, too, as evidenced with the part shown above for the printing industry. The shop had fixtured this long, relatively skinny part using only mechanical clamps on a tombstone for op. 10 and op. 20 work on one of its pallet-pool HMCs.

However, it was challenging and time-consuming for operators to mechanically secure either end of the part without causing it to twist about its longitudinal axis.

Rather than completely revamping the original fixture, Mr. Bray retained the mechanical clamping elements for the middle section of the part, but added two PAAW grippers to either end of the fixture.

Operators clamp the middle section of the part as they always have, but use the PAAW system to secure the ends of the part so these ends remain in a free state and there’s no chance of causing the part to twist.

After op. 10 work, the part is flipped and refixtured, and an op. 20 milling operation removes whatever cured adhesive remains from the op. 10 fixturing. Therefore, it’s only necessary to steam clean adhesive left behind from the op. 20 fixturing in this case.

Thus far, PGM has used the PAAW system for a couple dozen jobs in materials including aluminum, magnesium and stainless steel. Blue Photon says the PAAW system can also be used with composites and ceramics. The shop currently has three portable UV light source units that can easily be transported to machines throughout the shop.

The system will be used to a greater extent for production as well as toolroom work and CMM part inspection as PGM gains more experience with it and experiments with BlueGrip adhesives. Todd Hockenberger says it sometimes serves as a selling point for customers that are either having problems with other part vendors or readily recognize how tough their new design will be to fixture.

The shop has a good chance at winning those types of jobs once the customers understand how the system can be applied to their applications. In addition, it can help shorten product design cycles because fixture design is no longer the challenge it once was when mechanical clamps seemingly were the only option.

"This is big," Mr. Hockenberger says, "because PGM tries to get involved as early as possible in each customer’s new product design cycle to offer design for manufacturability (DFM) advice to minimize production time and cost, and get the product to the market faster."

Precision Grinding and Manufacturing: call 585-458-4300 or visit pgmcorp.com.