by Bernard Martin

Workholding Solutions
Recently, Jack Burley, the President and COO of BIG DAISHOWA, discussed innovative workholding solutions that are effective in combating vibration, with particular emphasis on the ROC® mineral cast solutions. These advanced solutions play a crucial role in increasing capacity and throughput by reducing burden and transport weights.

Much like a skyscraper, ROC® constructs a steel substructure for stability, precision machined and filled with ground positioning components and fasteners. The assembly is then encapsulated with a composite structure of mineral particles and epoxy resin, creating a working platform that is lightweight, yet stable and superbly dampened.

Mineral particles constitute about 90% of the added weight in these solutions, with the remainder being resin and curing agents. This composition results in an excellent density-to-weight ratio of 2.3 kg/dm^3.

The entire composite structure is produced without the application of heat, which preserves the integrity of the precision machined surfaces and clamping components. Furthermore, the low thermal conductivity and excellent resistance to corrosion of ROC® mineral cast enhance the durability and performance of the workholding solutions.

A key advantage of ROC® mineral cast is its exceptional attenuation rates, which are 6 to 10 times better than those of traditional grey cast iron, thus potentially increasing cell output significantly. ROC® mineral cast components are designed to resist impacts without disturbing the steel positioning and clamping components, due to their low tensile and impact strength.

Customizable to client specifications, ROC® also offers standard columns for horizontal machining center applications with options like integrated Unilock zero-point chucks or grid patterns.

Burley highlighted the ergonomic benefits and how ROC® mineral cast solutions facilitate machine capacity management in manufacturing settings.

Many of these solutions are about 50% lighter than their alternatives, making them highly advantageous for companies looking to standardize operator interfaces and streamline production processes.

By adopting ROC® mineral cast workholding solutions, manufacturers can significantly enhance their machining quality and operational efficiency.

For all BIG KAISER fine boring heads type AW, EW, EWN, EWD, EWE, EWB and EWB-UP, the frequency for lubrication depends on use.

If used daily, the recommendation is to oil the boring head every two to three months.

​The best procedure is to range the cartridge to the maximum diameter. Using a lubrication gun, pump oil in the unit until it stops accepting oil and then range cartridge to minimum setting. Excess oil will come out around the dial face (this is normal). If oil is excessively dirty, repeat the process.  

Recommended oils are Mobil Vactra No. 2, BP Energol HLP-D32, Kluber Isoflex PDP 94, or a similar light machine oil. 

By John Zaya, Product Specialist, BIG DAISHOWA—Americas

As the title implies adjusting screws, also known as back-up screws, stop screws and preset screws, are not just a simple set screw. They are a screw with a purpose--three actually.

The first is to provide a fixed stop for a cutting tool to rest against during tool changes. This allows an operator to save time as they do not have to pull out a ruler, setting jig, etc. to reassemble the cutter into a holder.

A secondary purpose of the adjusting screw is to assist the tool holder in keeping the cutter from being pushed up into the holder if the cutting loads increase to the point where the tool may slip up into the holder.

​The third is to offer sealing for coolant-through tools. 

When an old cutter is swapped out and a new one put in its place, the repeatability of this process will vary based on a few parameters such as cleanliness and the OEM cutting tool overall length tolerances.

Cleaning the clamping bore or collet of a holder provides better runout repeatability which should be old news to everyone, but if old coolant and contaminants are not removed, they would get jammed between the end face of the shank and the adjusting screw, affecting the length setting. 

Cutting tool overall length tolerances may also vary from one OEM to another. We have seen them range from ±.3mm to ±.5mm (±.012” to ±.019”). Others may be tighter or looser.

​Most modern machining centers come with tool length offset measurement systems which will provide the final precise gage length of a tool assembly. With the rough position provided by the adjusting screw, the machine operator can continue working and does not need to worry about tool clearances and stick outs. 

The clamping mechanism of the holder also affects the length repeatability. Both hydraulic chucks and milling chucks are radial clamping systems, whereas a tapered collet is drawn down into a taper by a threaded nut.

This draw down causes the cutter to be drawn down as well. For this we have two types of adjusting screws:

• HMA/HDA solid type - The solid type is a one-piece steel construction part
• NBA rubberized type - The rubberized type has a rubber padded conical pocket that absorbs the axial travel of the cutter shank as the collet is clamped. 

Milling chucks also have a second type of adjustment screw option that can be built into the back end of a reduction sleeve. As cutting tool diameters get smaller, the length of the shank also gets shorter.

​As such, the end face of the shank may not reach the HMA adjusting screw when installed it the body of the holder. The AC Type Collet adjuster screws into the back end of the reduction sleeve where the shank the tool can easily be reached. 

It is always recommended to consult the tool holder catalog or technical documentation to ensure that a holder can support an adjusting screw. Some holders are very short or have very deep internal features that may not allow for the use of any adjusting screw. In those cases, a depth setting ring or collar on the shank of the cutting tool may be an acceptable alternative. 

Caution should be used on shrink-fit holders. Thermal expansion/contraction occurs in all three axes, so as the body of a shrink-fit holder cools down it will draw the cutter down jamming onto the adjusting screw. This could lead to damage to the screw, the holder or the cutter. 

By John Zaya, Product Specialist, BIG DAISHOWA—Americas

T​he L:D ratio of a tool assembly is calculated by using the length of the bar (or body) of a tool assembly and the diameter of the tool, not the workpiece bore diameter and depth. 

To expand on this concept, we see in the first configuration below the Ø16mm bar is sticking out 160mm which is a 10:1 although the bore is only a 2.5:1.

In some applications this extra reach is needed to get around a fixture or a feature of the part. However, in those cases where it is not needed, decreasing the overhang by 55mm means the new L:D of 105:16 is 6.5:1. This alone would represent approximately 10x increase in cutting speed by increasing from 20mm/min vs. 200mm/min. 

The use of modular reductions has also been found to be a good strategy to improve tool performance.

Comparing the lower two assemblies below, the middle assembly uses the same connection size for the length of the tool, ignoring the larger access diameter, and results in a 6.4:1 ratio.

​When a shank with a larger connection size is used along with a modular reduction, the ratio is halved, and provides a 350% productivity improvement (14mm/min to 50mm/min).  
​
In all cases, reducing the L:D ratio provides an improvement in speed which then provides longer tool life, better surface finish and size control of the bore.  

By Matt Tegelman, Senior Product Specialist, BIG DAISHOWA—Americas
​Edited by Bernard Martin

 A common question asked for boring operations is when would I use a ground chip-breaker vs. a molded chip-breaker?

A ground chip-breaker is recommended for chip control issues. The high-positive rake angle will help to make shorter chips, and the chip groove orientation forces the chips forward to more easily evacuate them from the bore, especially when used with high-pressure coolant through the tool.

Ground chip-breaker inserts also provide lower cutting forces, so they are better suited for deep-boring or long-reach applications, and other situations where part or tool stability may not be optimal.

Ground chip-breakers are also recommended for tight-tolerance applications where stock allowance is typically light for the final size pass.
​
​A molded chip breaker is recommended for stable applications in short-chipping materials. Because these situations don’t require a super-sharp edge for cutting the material, these inserts hold their edge longer for better tool life, and in most cases are less expensive.

Hoffman Estates, IL - The BIG KAISER EWA Automatic Fine Boring System from BIG DAISHOWA performs closed-loop boring operations without a human operator. This breakthrough eliminates the need to stop the spindle to manually adjust the boring tool, which results in considerable time savings. Also, eliminating human interaction reduces cost, improves accuracy, and minimizes scrap. The adjustment range of this fine boring head allows for the handling of multiple bore sizes with the same tool and ensures a repeatable boring process. 

The EWA fine boring head is available in two sizes, one with a boring range of Ø2.677"-5.276" (Ø68-134mm) and the other with a range of Ø.394"-2.126" (Ø10-54mm). EWA kits are also available for each of these head sizes. These can include inserts, insert holders, a controller, antenna and protective case. 

The EWA can be used on machines with BT/BBT30-40-50, CV/BCV(SK)40-50, BIG CAPTO 5-6-8 and HSK-A63-80-100-125 spindles. The Automatic Fine Boring System can be integrated in three primary configurations: fully integrated, PC control, or tablet control. 

​Fully Integrated
A fully integrated system has the EWA control software running directly on the machine tool control via an app or technology cycle, requiring no external control device. The fully integrated system can only be integrated on new machine tools. 

​PC Control 
For legacy machines, a PC interface between the machine tool and the EWA can provide a fully automated, closed-loop control cycle. Commands are sent from the machine tool to the EWA, automatically adjusting the tool in synchronization with the machining process. 

The PC acts as a synchronization interface between the machine tool and the EWA. It stops the machining cycle after the touch probe makes a measurement, reads the result and sends the corresponding adjustment value to the EWA. After the EWA has been adjusted, the PC notifies the machine tool to continue the process. 

​Tablet Control
​The EWA can also be operated as a standalone tool, controlled manually with the BIG KAISER app on a tablet or smartphone. This enables the option to measure bores using an in-machine probe or manually, and to make fast adjustments in the app. Adjustments also can be done semi-automatically, where the head will move to pre-entered diameter values after a stoppage. 
To see the EWA Automatic Fine Boring System and other innovations from BIG DAISHOWA, visit booth #431610 at IMTS. 

By John Zaya, Product Specialist, BIG DAISHOWA—Americas

As the title implies adjusting screws, also known as back-up screws, stop screws and preset screws, are not just a simple set screw. They are a screw with a purpose--three actually.

The first is to provide a fixed stop for a cutting tool to rest against during tool changes. This allows an operator to save time as they do not have to pull out a ruler, setting jig, etc. to reassemble the cutter into a holder.

A secondary purpose of the adjusting screw is to assist the tool holder in keeping the cutter from being pushed up into the holder if the cutting loads increase to the point where the tool may slip up into the holder.

​The third is to offer sealing for coolant-through tools. ​

When an old cutter is swapped out and a new one put in its place, the repeatability of this process will vary based on a few parameters such as cleanliness and the OEM cutting tool overall length tolerances.

Cleaning the clamping bore or collet of a holder provides better runout repeatability which should be old news to everyone, but if old coolant and contaminants are not removed, they would get jammed between the end face of the shank and the adjusting screw, affecting the length setting. 

Cutting tool overall length tolerances may also vary from one OEM to another. We have seen them range from ±.3mm to ±.5mm (±.012” to ±.019”). Others may be tighter or looser.

​Most modern machining centers come with tool length offset measurement systems which will provide the final precise gage length of a tool assembly. With the rough position provided by the adjusting screw, the machine operator can continue working and does not need to worry about tool clearances and stick outs. 

The clamping mechanism of the holder also affects the length repeatability. Both hydraulic chucks and milling chucks are radial clamping systems, whereas a tapered collet is drawn down into a taper by a threaded nut. This draw down causes the cutter to be drawn down as well.

​For this we have two types of adjusting screws: HMA/HDA solid type and NBA rubberized type. The solid type is a one-piece steel construction part, whereas the rubberized type has a rubber padded conical pocket that absorbs the axial travel of the cutter shank as the collet is clamped. 

Milling chucks also have a second type of adjustment screw option that can be built into the back end of a reduction sleeve. As cutting tool diameters get smaller, the length of the shank also gets shorter.

​As such, the end face of the shank may not reach the HMA adjusting screw when installed it the body of the holder. The AC Type Collet adjuster screws into the back end of the reduction sleeve where the shank the tool can easily be reached. 

It is always recommended to consult the tool holder catalog or technical documentation to ensure that a holder can support an adjusting screw. Some holders are very short or have very deep internal features that may not allow for the use of any adjusting screw. In those cases, a depth setting ring or collar on the shank of the cutting tool may be an acceptable alternative. 

Caution should be used on shrink-fit holders. Thermal expansion/contraction occurs in all three axes, so as the body of a shrink-fit holder cools down it will draw the cutter down jamming onto the adjusting screw. This could lead to damage to the screw, the holder or the cutter. 

John Zaya, Product Specialist, explains the concepts behind the UNILOCK Zero-Point workholding system.

He also discusses base pallets and options for 5-axis machines.
Chapters:
0:00 Introduction
0:13 Basic Concepts
0:52 Features of the UNILOCK Clamping Knob
1:50 UNILOCK 5-Axis Program