Workholding, particularly for backworking operations, can be tricky when machining very small parts in a CNC Swiss-type lathe. Depending on their design, pickoff collets can produce a variety of problems, including poor concentricity and runout as well as poor control of clamping force, causing part damage. That is why when Dan Fifer, owner of Lane4 Precision (Santa Rosa, California) discovered collets that worked well for his applications, he became a dedicated customer of the manufacturer and trusted the company’s workholding system with his most delicate and complex parts.

In addition, Fifer says the Microconic collets enable fine adjustment of the collet tension on complex parts. These collets enabled the shop to machine parts it was formerly unable to create with other collets, as well as frequently and effectively perform backworking operations.

Although he quickly learned about the workholding necessary to machine his customers’ parts most efficiently, Fifer did not initially have experience with CNC Swiss-type machining. In fact, when he opened Lane4 Precision in 2017, he had never stood in front of a CNC machine control panel before, let alone a CNC Swiss-type lathe. His background was rooted in design/product development for the medical device industry. After working for several startups for over 20 years, he says he was anxious to be the one to create the parts instead of designing them.

So, he took his passion for innovation and rented a warehouse space where he decided to do all the machining processes in-house. He says someone told him he needed a screw machine to do the work he wanted to accomplish. The timing was good for him to attend IMTS 2016 to shop for a machine tool, and that’s where he met Spinetti Machinery, a distributor that sells Marubeni Citizen-Cincom Swiss-types. He was impressed with the machines’ predictability, and he was confident that the Spinetti team would support him and help him learn how to operate his first Swiss-type, a Citizen L20.

Once this sophisticated machine was set up, an industry colleague asked Fifer if he thought he could make a part that had already been designed. His colleague said no one could build it for him, not because it was not able to be done, but because the colleague did not want to wait 12 weeks to have the order complete.

“I said, well, I have nothing else to do, so I will figure it out,” Fifer says. “So, basically, within a month I was absolutely swamped from a team of about six engineers feeding me more parts that I was able to do.”
​
With Spinetti’s assistance, he has since selected four more of the Citizen Swiss lathes with different work envelopes and capabilities such as a live B-axis, automatic toolchanger and the machine tool builder’s low frequency vibration technology that helps create small, easily evacuated chips. The distributor was also responsible for introducing Fifer to the Microconic workholding system. A very small part on an L12 was the first job he ran with the workholding system.

Three-quarters of the machining done at Lane4 Precision, which is mostly a prototype shop, is for the medical industry, and the rest are premium parts for the semiconductor, defense, aerospace and consumer products industries, according to Fifer. Parts range in size from fitting within a work envelope of a grain of rice (length or diameter of a half a millimeter or so) to long slender parts over two feet long.

Because some parts produced by the shop contain thin walls and have short pickoff lands, it was critical that the workholding system installed offer acceptable tool clearances and fine adjustability for subspindle backworking. The shop also needed compact and reliable over-grip collets for the most complex applications (more about that later). Fifer found his expectations met and then some after installing the Microconic workholding system. In fact, he was so pleased that he eventually added it to all five of his Swiss-types.

Masa Tool, which only specializes in subspindle collet workholding, has designed the Microconic workholding system which consists of cartridges that are installed in a machine like a standard collet. The cartridge, which offers 0.0002-inch TIR, can be used as a gage to verify machine spindle accuracy. Also, the adjustment dial wrench offers precise and repeatable control of the clamping force, according to the company. Because the cartridge is built with an extended nose, extended nose collets are not necessary, making this system well-suited for Lane4 Precision considering most of its applications require an extended nose pickoff collet. Fifer explains that the Masa collet closure mechanism has been moved right up to the collet nose, improving rigidity relative to standard extended nose collets.
​
All Masa collets fit into the machine’s cartridge or an adaptor sleeve from the company, making it easy for Fifer to change back and forth between collet styles on all his lathes.

He also points out that it usually takes only 5 minutes when changing over his lathes from machining “large” parts (which for Lane4 are those that are a half-inch diameter and larger) to machining smaller parts when using the Microconic collets. According to Masa, the changeover from a 16C to a 5C collet usually results in a tolerance accumulation and can sometimes take more than 15 minutes to change the collets. But, with the Masa system, once the cartridge is in place, collets can be quickly installed and clamping pressure set right at the spindle nose without tolerance stackup in less than a minute.

Fifer also appreciates Masa’s over-grip collets for parts that require those. He explains that, although these collets are compact, they offer a large opening and rigid holding. He says they outperform any alternatives he has tried in the past. “My cycle times, rigidity, tooling, everything is better,” he says. “They took away the fear of doing over-grip parts.”

However, the over-grip collets open up to 0.156-inch diameter larger than the holding diameter. According to Masa, these collets are still capable of 0.0002 inch of TIR. With such reliable gripping, Lane4 Precision has been able to expand its capabilities, even machining some intricate parts “backward,” providing higher quality parts, with fewer defects and a lower scrap rate, enabling operation without interruption.

While learning the ins and outs of the Microconic system, Fifer says he realized how much confidence the workholding system’s design has given him to complete high-quality and miniature parts for his customers.For example, he appreciates that the collet nose is not chamfered. This design leaves more room for pickoff, he explains. “I used to have to face the collet before I could use it, so I could know what I was dealing with. But then it would alter the length of the collet.”
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The advantages of excellent runout on the workholding system is another realization Fifer came to after he started putting it to use. It is possible to put very fine features on the backside of a part and maintain concentricity while also producing a “pretty” part. “If you have a 0.005-inch wall and you are trying to put 0.001-inch edge break on it, and you’ve got 0.001 inch of runout, the result is a really ugly part,” Fifer explains. “Using a Masa Microconic collet is like firm footing from the subspindle. At least you know you are starting in a good place for the most critical applications.”

Since 1973, Micro-Matics of Fridley, MN, has been manufacturing CNC Swiss precision screw machine products including many kinds of contacts & pins, ground shafts, hardened bushings, rivets, screws, spacers and other custom parts for the medical, dental, aerospace, commercial, defense, computer, telecommunications and automotive industries.

According to Jason Wobig, Operations Manager, "Micro-Matics is primarily an aerospace and medical components, Swiss machining job shop. We make components that are thousandths of an inch up to an 1-1/4" in diameter. We started out with the old manual style, Cam driven Swiss machines and we're one of the largest Escomatic shops in the Midwest.  And as the company's grown and evolved, we've turned into Swiss job shop, mostly Citizen machines like the M16,  a L12, and a M32, as well as a few Star and Tsugami machines that give us a wide variety of capabilities."

In 1996, Matt Saccomanno, CEO of Masa Tool, was frustrated with the limitations of conventional collets and workholding systems when performing secondary machining operations so his solution was to develop a high-precision, collet-type workholding device for small parts machining.

The Microconic system consists of a cartridge and collet, with the cartridge fitting in the machine just like a standard legacy collet. The cartridge is a self-contained precision mechanism using the machine’s standard collet closing function, which means that the Microconic system can be used on any machine utilizing 5C, TF20, TF25 or TF37 collets. 

According to Saccomanno "Since a collet system for any given machine must be made large enough to fit the maximum workpiece diameter capacity of the machine, the result is the standard collet mechanism is designed to handle the largest workpieces, which means it is excessively forceful and bulky when used for the smaller workpieces. Smaller parts get sacrificed, because they typically require a higher degree of accuracy and the workholding is more critical."

The Microconic system consists of the cartridge, which fits into your machine like a standard collet, and the Microconic collets which fit into Masa's unique cartridge.  Every Microconic cartridge comes standard with extended nose for unsurpassed rigidity because of it's single piece construction.

"In fact, the cartridge is so accurate that it can be used as a gauge to verify machine spindle accuracy," said Pakiz.

Thayer explained how the Microconic system has worked for Micro-Matics "With the Masa system we're able to dial in a nice specific tension to hold that catheter part without crushing it or deforming it at all and having it on center.  In a nutshell, we get better quality parts consistently with tighter tolerances. It's lead to a really significant improvement, it's increased throughput, so we have more parts at the end of the day."

"As a result of the implementation, the scrap rate on this part dropped dramatically once we added the new Masa system by at least 30%." added Wobig. 

According to Masa Tool, the Microconic cartridge  concentricity is guaranteed to be within 5µm (.0002") runnout and the collets are hardened and precision ground to the highest quality standards. The regular, UM10,  10mm collets, that  Micro-Matics is using in their F20M10 Cartidge are available from Ø0.2mm (.008") to 10mm (.394").  In additon to the TF 20 spindles, the same collets can be used in TF25, TF37 and 5C sub spindles.

"With the Microconic system, we didn't need to buy any special collets for any specific profile, we just got the actual diameter for the OD of the part and we're running it with that. The spaces in between on that collet is small enough that it's not distorting the round to flat portion if it even gets into there at all. So there's no timing issues at set-up. We just put it in there, set our tension, and start picking them off." added Wobig

Thayer continued "The extended nose pieces on the Microconic cartridge helps on the catheter tips because  you can get closer up to where I actually have a supporting back end.   Because if I'm too far away from that supporting back and you have more of a tendency to crush the front of that part. The Microconic gives me a better tension on the part.  On the distal coupler, we have to use a boring bar, or a facing tool to create the back face, which is round. We'd have a lot of trouble trying to hold without nibs or anything on there. And this holds it so that the part stays a little more square, and we're able to turn it better."

When dealing with very small parts and setting with small gage pins, accidents do sometimes happen.  "The only problem I've had with it was when somebody was trying to set the collet tension with a pin. They put the pin into the slot and not the hole and wrecked the collet. Because the pin was able to fit inside the slot so when they started tightening it up, and the pins started deforming the collet was wrecked because it wasn't in the hole in the center." said Thayer.

Masa has indicated that they will release a new TF 15 and TF16 Cartridge with an entire series of smaller 5mm capacity collets at IMTS 2022.

Designed for the clamping of micro-workpieces in the sub-spindles of sliding-head turning machines, Floyd Automatic Tooling, in association with Masa Tool of the USA, has released the Microconic system into the UK marketplace. The Microconicworkholding system consists of a cartridge and precision collet. Importantly, no machine adaptations are required: the collet fits inside the cartridge and is adjusted before being fitted directly into the existing collet sleeve.

With a concentricity level of between 3 to 5 µm, Microconic is suitable for sliding-head lathe marques including Tornos, Citizen and Star. It is currently available for F20 and F25 style collets, with F37 versions in development. A 5C version can also be offered.

The cartridge system incorporates a solid extended nose and has the facility for micron-adjustment of the collet closure. To confirm precision levels, the hardened and ground cartridges can be used as gauges to verify spindle accuracy.

Masa’s Microconic also includes ‘over-grip’ collets where clamping behind a shoulder is necessary, for example. The cartridge/collet combination can accommodate openings more than 4 mm larger than the clamping diameter (depending on the application). This flexibility offers production engineers the potential to machine the part the other way around, which can sometimes help improve cycle times.

Microconic collets are available in 0.05 mm increments from 0.22 to 10 mm diameter. Each collet has a nominal clamping range from 0.05 to 0.1 mm depending upon the chosen collet diameter. With regard to the over-grip collets, the nominal clamping diameter starts at 0.5 mm with a maximum clamping diameter of 7.2 mm.

For further information
www.floydautomatic.co.uk

This article originally appeared in Machinery Trade International

Masa Tool’s Microconic T-type over-grip collet features a longer gripping surface for holding longer parts. The collet can open as wide as 3.5 mm (0.138") over the chucking diameter and runs within 5 microns (0.0002") TIR.

The collet is designed for use with longer parts such as bonescrews with wide-pitch threads; orthopedic surgical drills and taps; long shafts with flange; long, thin-walled tubular parts and long plastic parts.

Extra spread is required to open the collet wide enough to go over the larger diameter. The correct over-grip collet for a specific part can be chosen based on grip diameter, width of the grip land and the largest diameter of the part.

According to the company, the collet expands machine capability, eliminates secondary operations and reduces cycle time. It features a standard gripping land length of two-to-three times the diameter. It is available with diameters ranging from 1.55 mm to 7.2 mm (0.061" -0.283").

The collet is said to grip with the same rigidity and accuracy as regular collets and features a fatigue-tested design built to last more than 250,000 full-load cycles. The collets are compatible with the company’s cartridges and come with its Microguide Brass ejection guide sleeve blank.

The push-type F201M10 micro-workholding cartridge system replaces F20-201 cartridges allowing the user of Microconic collets to achieve concentricity within 5µm (0.0002") in production use.

For use in high precision, small diameter CNC turning applications, it enables users to move more work to the sub-spindle for reduced cycle time.

The F201M10 cartridge is compatible with spindles that accept F20-201 collets including DIN 136E, Meister Swiss 136E, Schaublin F20 (76-201), Southwick & Meister F20-201, KEB (MasWerks) MC20-201, and Hardinge F20-201/4709 collets.

This article originally appeared in
Today's Medical Developments
July 5, 2018

Masa Tool’s Microconic push-type F201M10 cartridge pairs with its Microconic collets for concentricity said to be within 5 microns (0.0002") in production use. The cartridge is a micro-workholding system for use in high-precision, small-diameter CNC turning applications. The cartridge is compatible with spindles that accept F20-201 collets.

The cartridge and accompanying collet are designed to vector the chucking force directly over the holding surface, reducing the chucking force while also increasing the holding power. This reduces chucking damage on the workpiece and reduces cycle times by 20 to 40 percent, the company says. 

The cartridge’s solid extended nose enables access for tooling and coolant with minimal overhang. Its core diameter is a single-piece construction that is designed to maintain 5 microns (0.002") concentricity at the extended nose tip. Used with the company’s Micrograd wrench, the cartridge features micrometer dial control of collet clamping pressure regardless of the machine’s hydraulic or pneumatic collet closing force. The cartridge is suited for small-diameter parts ranging from 0.22 mm (0.008") to 10 mm (0.3934") in diameter.

"Micro-movement" of the workpiece is reduced, resulting in a longer tool life, better finishes, fewer chatter problems, and less damage to the workpiece. The cartridge eliminates secondary operations, saves time and enables operations to be done in the subspindle. Broaching, milling, saw cutting/slotting, turning, boring and drilling can be machined in the subspindle.

CEOCFO:
Mr. Saccomanno, what is the idea at Masa Tool, Inc?  What is your Microconic
Workholding System

Mr. Saccomanno:
Masa Tool is basically formed from our life experience in the machining of micro-precision parts; primarily on Swiss-type screw machines, although the real focus is for high precision small parts manufacturing on any machine type
to better the world of micro machining. Specifically, our first major product release is the Microconic line,

as you mentioned. Microconic is a high precision, collet-type workholding system that fits in conventional machine tools of all types. It provides extremely precise, extremely rigid and also very easy to use workholding for the manufacturing of micro precision products.

CEOCFO:
What are you replacing or enhancing? What are people doing now?

Mr. Saccomanno:
We are replacing an existing collet design. A collet is a traditional workholding device. It is like a split sleeve that has a taper on it and it slides into another tapered receptacle. It clamps down on the work piece and traditionally has been the most precise and rigid way to hold small work pieces for production machining. The most widely
used collet system design was invented about a hundred years ago. It has essentially been used to this day with very little improvement until now. The Microconic system was created to resolve many of the limitations of existing legacy systems.

The neat thing about Microconic is that we fit directly into the existing legacy workholding system, so that it is an
advanced, self contained workholding unit that fits within what is already in the machine. Therefore, the costumer does not have to modify their machine or anything. They can install our product right inside their existing spindle. Then we provide improved accuracy, repeatability, adjustability, consistency, rigidity and everything in every way. There are quite a few different ways that we improved the state of the art.

CEOCFO:
Have manufacturers been looking for a better way or is it once they find Microconic they are excited?

Mr. Saccomanno:
That is a great question! There is excitement when they see what we have, but it is not an easy sell at first. That is because, as you say, it is hard to look for something that you do not know exists. That has been a big part of our marketing hurdle to get over; to distinguish ourselves from the systems that are out there. To answer your question it is both a yes and a no answer. Yes, people have been looking for something else. There are pervasive complaints
throughout the industry about the quality of existing systems and the availability and the consistency. Those are just like part of the landscape. They have been around for years.

Everyone is kind of used to dealing with it and they are always trying to find better sources to get better collets and things like that. On the flip side, because people are so used to dealing with that, they do not really anticipate the revolutionary change that you can get by all of the benefits of the Microconic system. Therefore, it takes a skilled technical person to really talk to the customers specifically about what they can do with their own applications. The cost of Microconic is not trivial, so it is important to show how the value is created by providing capabilities to significantly improve productivity over what can be done with traditional legacy collets.

Microconic’s cartridge is made of exotic high-chromium tool steel, triple tempered and cryogenically treated to provide stable construction. All functional seating surfaces are ground with extreme precision on a one-piece, ultra-rigid body structure.

“The cartridge can be used as a calibration gage to verify the machine spindle accuracy,” Co-owner Chip Prescott notes.

Microconic collets are finished to exacting standards with a five-step grinding process that removes the effect of heat-treat warpage. Also, the proprietary Microconic form of the closure surfaces is inherently more accurate than traditional collets, providing for a greater full-accuracy working range.

Cartridges are available to fit in push-type dead-length collet closers and also draw-type closers: F20M10 (for TF20 collet replacement), F25M10 (for TF25 collet replacement), and 5CM10 (for 5C collet replacement). All of these cartridges use the same Microconic UM10 collets, with more cartridge sizes in development to be released soon.

Masa Tool is introducing its Microconic workholding system for use in subspindle Swiss-type machine operations, enabling the operator to switch operations from the main to the subspindle so that usage is balanced. This capability is said to reduce cycle time in ways that are not possible with conventional collets.

​The Microconic system consists of two primary components: a cartridge that fits in the machine’s standard TF20, TF25 or 5C collet closer, and the collet itself, which fits into the cartridge. Each cartridge model has a solid extended nose and can accept both regular and over-grip collets. The over-grip collets open up to 0.157" (4 mm) larger than the clamping diameter.

​The Microconic cartridge’s extended nose design directs all of the chucking pressure directly over the workpiece for concentricity and rigidity. Total indicated runout (TIR) for the Microconic system is guaranteed at 0.0002" (5 µm) at the workpiece, absent any runout introduced by the machine structure or other elements of the setup. The system capacity ranges from 0.008" to 0.394" (0.2 to 10 mm) in diameter, with all sizes available from stock.