Rules of Swiss-Type Machining: Micro-Boring

The number-one rule of Swiss-type machining – the process is the product. Swiss-type machinists work smart. Less effort, less machine time, longer tool life and maximum repeatability. Producing the most precise pieces while achieving quicker turnaround times with improved tool life is the ultimate goal for any manufacturing shop.

Let’s face it, if you are micromachining metal materials, then you’re probably performing hole making operations more than anything. Micro-boring is another step in perfecting a hole on the microscale, but it is easy to screw up, and you will want to get the process right for each and every job.

As we discussed last week while covering micro-reaming, boring is a process in which a single point tool enlarges an existing hole in the workpiece to help give the hole a more cylindrical diameter through the hole's length. The boring operation is a much more delicate process on the microscale than you might think. At GenSwiss, we want to make machinists’ lives easier, so this installment of Rules of Swiss-Type Machining going over micro-boring, how it can differentiate from the traditional method, best practices for the best results, and more.?

So, why the heck do I need to know about this stuff? When it comes to machining high-precision parts, everyone needs to be a perfectionist.

If you are using a CNC Swiss machine to manufacture for aerospace, automotive, medical and/or telecommunications industries, then you know that the demand is as high as the stakes. That means you need to choose the right tools and match them to the correct operation for producing the highest quality workpiece with a high level of repeatability and quick turnaround times for each and every job.

The first rule of micro-boring is that a boring bar is only as good as the holder that it is in. GenSwiss offers several options, including MicroBore tool holders manufactured by Utilis, GenSwiss’ brand new GenQuick adaptor product line and signature GenGrip hydraulically actuated clamping tool holders, all providing reliable positioning and optimal rigidity each and every time.

MicroBore Holders

"Because precision is of the essence, it’s critical to choose tools with inserts that have a secure clamping system that guarantees correct positioning of the cutting edge,” said Patrick Loughney, product manager of small part machining at Sandvik Additive Manufacturing, in the article Tooling Up For Micromachining featured in Production Machining.

How can you easily achieve this? The magic of a positive stop pin. A positive stop pin guarantees the micro-boring bar’s correct orientation and boring location each and every time. Boring bars from GenSwiss all feature an angled back end that locates within .0002 inch against the positive stop pin contained within the micro-boring bar holder.

“So, the bore bar is always going back into the same exact location,” said William Fletcher, Northeast Regional Sales Manager at GenSwiss.

A fine-pitch thread knurled nut provides force against the boring bar’s internal snap ring to allow the operator to insert a boring bar into the holder and tighten it by hand.

“It’s as simple as removing the boring bar. No wrench involved with it. So, it’s finger-tight while you’re working in the machine. No vice grips or anything. You keep all of your tools away from it. The benefit there is that you can’t distort the holder by overtightening it,” said Scott Laprade, GenSwiss Inc. applications and tech supervisor.

“The boring bars actually work in conjunction with the holder in such a way that there’s a carbide pin internally in the holder bore which goes up against the back.”

According to Utilis, the SDA version of the micro-boring bar holder is made of high-grade tempered steel, can be inserted into standard clamping systems, and holds 4, 6 and 8 mm cutting tool shank sizes, with the cutting geometry sizes ranging from 8 mm to less then 1mm.

“The cutter replacement is carried out manually and, as a rule, does not require a readjustment of the axial and radial positioning,” said a statement from Utilis.

“The Superclamp holder offers more stability and holding power for special machining processes such as multi-sided punching, hard turning with CBN as well as achieving the finest surface finishing qualities in non-ferrous production with PCD, CVD or MKD tipped tools.”

An AKR Dogleg holder is also available for external work off of the gang slide, Utilis noted.

GenSwiss also offers reduction sleeves to convert micro-boring bars from imperial to metric or to increase the ? size from 12 to 16 mm or 16 to 22 mm.

The ease of repeatability is only one part of the magic. All MicroBore holders and boring bars from GenSwiss have coolant-thru capability. These Nano-cooling kits feature all of the plumbing and fittings that an operator typically needs in one setup.

“If you got a situation where concentricity is paramount, this entire system is a great choice,” said Laprade.

Fletcher noted that Nano-cooling kits feature plumbing parts in three different lengths and can withstand over 3,000 psi.

What about tool rigidity?

“Vibration is the biggest enemy of the boring bar,” said Laprade.

MicroBore tools’ grooves and a multi-faceted necks reduce vibration and improve cutting performance for precisely machining small parts from all standard materials. The line also includes both coated and uncoated carbide grades that are resilient enough for cutting tougher materials that are too difficult to be efficiently cut by standard tools. These features optimize your machine’s ability to cut precisely while maximizing repeatability and tool life.

“For powerful operations (such as rough boring, turning or facing), be sure to use the hand of tooling that causes the force of the machining operation to be absorbed by the bed and way systems of the machine, or else the machining operation forces will tend to pull the machine components apart, causing play in the way systems. Over time, the machine will develop chatter and sizing issues.,” said Mike Lynch, founder and president of CNC Concepts Inc., in his piece Five Safety Considerations for CNC Machinists for Modern Machine Shop.

GenSwiss’ GenQuick Adaptors

Quick-change capabilities are only a hand turn away with all of GenSwiss’ micro-boring systems, but you can get your process going even quicker.

GenSwiss’ GenQuick adaptors are a fast and simple solution for locating the center position for boring bars when combined with notched extended range holders, allowing operators to locate the boring bar axial and radial positions at a quicker rate.

“Even prior to a post-COVID job market, it was very difficult to find qualified operators capable of setting up and running CNC equipment to the level of precision that is necessary to meet most production requirements,” said Laprade.

“The newly redesigned GenQuick tooling system helps new users as well as seasoned veterans achieve faster setups and tool changes through the use of tool holder adaptors and quick-change modules that can be preset and are based on the ER standard tool holding system.”

Solid bushings utilizing the GenQuick tooling system securely hold the boring bar in a rigidly, and axial length can be easily set with your presetting device. As with GenSwiss’ other holders, a locating pin rests within the notched holder to provide accurate centering. With both single and double holders available, you can greatly reduce production times, minimize errors, and create an overall safer process. ?

Tooling

So, what are the best boring bars, and can I enhance these tools?

In partnership with Utilis, GenSwiss offers over 150 different tools that have extremely sharp cutting edges, small corner radius, and ground chip breakers. The MicroBore line provides a range of more than 15 standard cutters with tool nose ? (dim a) ranging from 0.38 to 7.13 mm (.015 - .280 inch). A complete ID working system that is capable of performing boring, grooving, profiling, chamfering, threading operations and more, all tools are made from high-grade carbide. MicroBore cutting tools are coated with UHM20 HX. Other coatings, such as the new exotic materials coating TX+, are available upon request for unique applications.

You will learn much, much more about different boring bars, and their specific operations and industry applications, in future installments of Rules of Swiss-Type Machining.

Explore GenSwiss micro-boring bars and holders:

• Boring Tools
• MicroBore Holders
• GenGrip Hydraulically Clamping Boring Sleeves
• Quick Change Boring Adaptor

Want even more Rules of Swiss-Type Machining? Check out our installments covering Micro-Reaming and Thread Whirling.

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More about GenSwiss…

Genevieve Swiss Industries, Inc.?brings to market unique high precision tools and accessories, advancing small parts manufacturing and enhancing Swiss-type machine processes. Our high quality product line of cutting tools, machine tool holders, and live spindles are imported from three of Switzerland’s primarily world-class manufacturers:?PCM Willen SA,?UTILIS AG, and?Louis Belet SA.?

With more than 35-years of experience in the industry, GenSwiss aims to improve distribution efficiencies and increase manufacturing productivity. We strive to deliver products which meet or exceeds customer expectations, providing a reliable service with application solutions for YOUR critical small parts manufacturing.

Our own GenSwiss designed and manufactured?Signature Series?products are becoming a favorite among CNC Swiss-style machinists.?These products include high quality rotary?broach tools,?Ti-Loc? extensions?and?saw arbors,?high precision straight shank saw arbors,?compact straddle knurl holders, and?many more.

Have any questions about your Swiss machine holders, tools, and attachments? Reach out to the CNC Swiss machining experts! GenSwiss is here to make your Swiss machining job easier. It is more than Swiss turning, it’s a lifestyle.??