To avoid crushing and ruining parts, Swiss precision manufacturer Micro-Matics turned to Masa Tool’s Microconic collet and cartridge system.
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."
A while back Micro-Matics was running a small medical part, a catheter part, that they were struggling with.
They had some custom collets made for pickoff and, according to Dave Thayer, Department Manager,
"It was a constant struggle. This particular catheter part has very thin walls, it got crushed with a standard M16 collet system because you have very little accuracy in how much tension you're putting on your collet. If you put too much force on it, my parts started turning to collapse into triangles. If you don't have enough tension on it, the part pushes back into the pickoff and you get varying part lengths and varying chamfer diameters. The parts would be out round and they wouldn't be on-center."
Wobig had heard about Masa Tool's Microconic™ sytems through Todd Pakiz, President of High Tech Representation Inc., New Prague, Minnesota. "Todd had told me about this system a couple years back. And we had been struggling with these parts. So I reached out to Todd and see if he's still selling that system."
Wobig continues, "I wanted to try this system for the catheter part which is a small thin-walled part approximately 0.040" in diameter and another 0.040" in length and with a wall thickness of 0.010". So I wanted something that wasn't crushing the part. It was really hard to adjust the machines pickoff spindle itself to any degree of accuracy without crushing a part."
What Wobig found with the Masa Microconic system was that they could set up the clamping with a gage pin and set the clamping tension with the Micrograd™ Dial Wrench which has little indicators to set an actual tension.
Cartridge and collet solution
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.
Applying technology to other applications
Micro-Matics has been running one of the collets for a couple of months straight now on a distal coupler.
Thayer explains, "The distal coupler part has a unique shape. It's not perfectly round. It has some small flats milled on either side of the part. It's like a cylindrical pill, like a capsule except with two sides of the long length milled in so there's flats on it. The part is 0.080" in length 0.040" in a cylindrical diameter. We then mill the cylindrical diameter 180 degrees from each other to a thickness of 0.030", so you're taking 0.10" off then drilling and centering two holes on each end of that through the flats."
"Our customer is extremely concerned about any collet indication marks or chip marks on the outside of that cylindrical diameter. The previous collets we were using were custom made collets that actually had the profile of the part basically machined into it" says Wobig.
Thayer picks it up, "It was a straight cylinder round collet it but it was split in half so it was like two halves of a collet so we were trying to keep the flats in the spaces and then the round cylinder on the collet part that's round. The holding portion it would move and we didn't have them pinned at all. And then we had the same issue as on the catheter part: If you squeeze it too tight you're starting to push the diameter into the flat so it would deform the OD into the flat and make deformed flats. If you squeezed it too hard, it would make the flat bump up. If it didn't sit perfectly right in the custom collet you'd have the split marks of the collet that start interfering with the transition between the flat to the diameter and it would make lines on the diameter."
Remedying the issues
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.
Microconic over-grip collets have unmatched rigidity and concentricity compared to other manufacturers. The same collets can be used in TF20, TF25, and 5C sub spindles. Microconic collets permit interchangeability between machines, and the collets fit in any Microconic cartridge, no matter which collet system is in the machine.
Swiss Machine Workholding Cartridges
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.
- Solid extended nose, minimal overhang
- Single piece construction of cartridge’s core diameter.
- Maintains 5µm (0.0002") concentricity at extended nose tip.
- Micrometer dial control of collet clamping pressure when using Micrograd Wrench.
- Suited for part diameters sizes from 0.2mm (0.0080") to 10.0mm (0.3934").
Today's Medical Developments
July 5, 2018
It was the cover story entitled: "Micro-Precision Machining" by Elizabeth Modic
Titanium alloy bar stock
Star SR20 Swiss-type CNC Automatic Lathe
The dental implant was machined almost entirely on the main spindle of the machine due to the need to have a powerful grip on the bar for a high-force, blind-hole, hexagon broach. Very little work was done on the pick-off spindle, so that sat idle for most of the cycle.
Cycle time reduction:
164 sec. to 98 sec. per part; 40% improvement achieved by moving all ID machining operations to the pick-off spindle, where they were performed in shaded time while the main spindle completed the OD. This was previously impossible to do with legacy collets, because the broaching force would push the part back in the collet. The 0.001" concentricity requirement of ID to OD could not be reliably achieved with legacy extended-nose collets, and they damaged the critical surface finish on the OD of the implant.
Production rate went from 18pph to 32pph, a 44% cost savings. In addition, a hand deburring operation was eliminated due to the cut-off being on the opposite end.
Cost of the Microconic system was recouped in 64 production hours; a $14,015 saved in direct production costs of a 10,000-piece order.
Workholding: Design and Function
It was the cover story entitled: "Micro-Precision Machining" by Elizabeth Modic
“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.
It was the cover story entitled: "Micro-Precision Machining"
By Elizabeth Modic
In 1996, Matt Saccomanno, co-founder of Masa Tool, was frustrated with the limitations of conventional collets and workholding systems when performing secondary machining operations as engineering manager at Allied Swiss Screw Products.
This was in the early days of CNC Swiss-type machines, when machining capabilities were limited, requiring lots of secondary operations. His solution – a high-precision, collet-type workholding device for small parts machining.
As machining capabilities advanced and precision requirements became more challenging, Saccomanno realized that the legacy collet systems used in micro-machining were a serious limiting factor that prevented full use of modern machine capabilities.
That prompted Saccomanno to design the next generation, the Microconic system.
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