There are many different types of tool holders that can be used for different applications. Using the right tool holder for your job can impact many aspects of the machining process, including the speed at which the machine is able to run. If the tool holder you are using is high, with a low runout and high rigidity, it allows the cutting tools to run at a much higher RPM. The biggest advantage to this, and why we recommend high performance tooling alongside suitably high-performance tool holders, is the cost-saving benefits; saving the amount of downtime you will experiencing and allowing you to complete more jobs in a set time in a time-effective manner. On the flip side, if the tool holder you are using is not suitable for your set-up (for instance, using a standard ER collet chuck for high-speed cutting of a tough material), this can cause wear on the tool holder and also tool wear, potentially causing it to chip or even snap. Collets can also not be evenly pressed into the tool holder.
Having the right tool holder in your machine can also significantly help with the repeatability of high-volume jobs and ensure that all your workpieces are machined to the same standards. This can increase productivity, improve process efficiencies and allow more high-volume jobs to run in a shorter time period, without the worry that workpieces will need to be scrapped due to not conforming to specified tolerances. Sometimes, when using tool holders that aren’t suitable for your machining set-up, it can cause the machine to stall or even damage the spindle – having huge cost implications and also causing major downtime whilst the machine is serviced or replaced.
Spindle tooling refers to a collection of tooling which fits into a manual or CNC machine’s spindle, hence the name ‘spindle tooling’. The end of the tool holder which connects to the machine will feature the same taper as the machines. Common tapers include BT MAS (JIS B 9339), SK (DIN 69871), HSK (DIN 69893), ISO (DIN 2080), Straight Shank and Morse Taper (MT). The connection chosen will have little bearing on the quality of the toolholder but is just a reflection of the make and model of the machine. At the other end of a tool holder will be the cutting tool.Usually, the cutting tool is directly clamped into the tool holder, with certain types of spindle tooling (commonly ER Collet Chucks) instead use an intermediatory to clamp the tool into the holder, usually a collet. A collet will have a clamping range, by which tools with diameter shanks within this range can be clamped. The collet is then clamped within the tool holder, which is then ready to be used.
Depending on the application or performance level required, there are different tool holding options available. If you’re using very cost-efficient tooling (for instance HSS or powder metal milling cutters or drills), it makes sense for a standard run-out holder to be used. This could be a basic ER collet chuck, end mill holder or face mill holder with standard 10 micron run-out collets. Of course, you can use a high precision collet in a standard tool holder, but you will be limited on the cutting data you can run a tool at and the vibration within such a set-up.
When using carbide tooling (or any tooling which is defined as ‘high performance’, ‘premium’ or has a sizeable cost attached to it), it is important that the tool holding matches that of the tool making contact with the workpiece. Hydraulic chucks and heat shrink chucks (also referred to as shrink fit chucks) are two popular options when dealing with high performance tooling. Both offer higher run-out accuracies and increased tool life over conventional tool holders. Differences between the two are mainly the way in which the tool clamps into the holder; hydraulic chucks fill with hydraulic fluid which pressurises, closing the bore of the holder and clamps the tool in place, whilst shrink fit chucks use specialist machines to heat the chuck, which causes the chuck to ‘shrink’ and mould around the tool. For tapping, the equivalent high performance tool holder would be a synchro tap chuck.
Why would you choose a high-performance tool holder over a standard tool holder?
A high-performance tool holder can offer several different benefits. Most high quality/high-performance tool holders will offer excellent rigidity, accuracy, high clamping power and dynamic balancing – this is all to suit the machine and the maximum spindle speed.
Using a high-performance tool holder can also have implications on the outcome of a job or workpiece. By using a performance tool holder, you can decrease the expected run-out, hence increasing the accuracy of your tool and also the tool life. The amount of run-out that a tool will experience will cause it to wear due to the increased vibrations (vibration causes tool wear, spindle wear and tool failure, as well as a poor surface finish on your workpiece).
High-performance tool holders also usually have a higher balance rating. A higher balance rating can affect the efficiency of work. When a tool holder has a high balance rating, the G value will be lower; the lower the G rating, the better the tool holder will be for your work (this can also depend on the application, the machine you are using and the cutting data of the tool you are using).
Another factor that can affect the efficiency of your tool holder is the gripping force. High-performance tool holders will have a higher gripping torque; the higher the gripping torque is on a tool holder, the more efficiently it will be able to run. A tool holder with a low gripping torque is more likely to run the risk of tool pull out.
A huge factor that can impact the performance of a tool holder is rigidity. The higher the rigidity of a tool holder, the longer the tool life will be. The most high-performance tool holders will offer a combination of high rigidity and good dampening qualities, which allows the tools to work through vibration without decreasing the quality of the surface finish or damaging the tool.
Arguably, one of the most crucial things to look at when purchasing a tool holder is the accuracy the tool holder provides. The accuracy of a tool holder can play a huge role in affecting the tolerance of the completed product and the machine’s ability to complete instructions and produce components to precise dimensions. When tool holders have increased levels of accuracy (usually characterised by low run-out, higher balancing and a higher quality material body), it is usually accompanied by improved productivity, better surface finish, lower downtime (due to not needing to replace tooling as frequently) and increased cutting speeds without sacrificing precision.
Tool holders (toolholders) are the main facet that connects the machine tool to the tooling.. Their mounting styles are all different according to the interface. Their mounts can range from HSK tool holders, VDI mount, or the dated R8 styles.
All types of tool holders consist of 3 unique parts: the collet pocket, the flange, and the taper. There is static tooling which is not powered and there is live (driven) tooling which is not powered.
A variety of tool holders surround the cutting tool (machine tool) so it remains intact in one position – while many other machining tools enable maximized clearance for small to large sizes.
There are a wide variety of tool-holder types, they are indexed in the industrial machine tooling databases as such:
When you but tool holders, you should consider the exact mounting style that you need..
R8 is an old school mount developed by Bridgeport back in 1965. This part is obsolete and rarely used in modern machine tooling.
The Morse taper (MT) is manufactured in 4 different sizes. Every size differential contains a unique taper for ease of transitional changes in tool fittings and machinery tool use.
National Machine Tool Builders (NMTB) defined
The NMTB taper type of toolholder was defined by (NMBT) National Machine Tool Builders. It is used in all types of milling CNC machinery and machines. The basic measurement requires a draw bar and stands at 3.5 inches per foot.
The CAT® by Caterpillar®developed customized mount style, is mainly referred to the V-flange. It is the very basic tool for Cat CNC machines. All tool-holders built and manufactured by Cat consist of a numerical ID associated with taper size. (examples CAT-30, CAT-40, CAT-50 and CAT-60.)
Similar to the popular Cat tooling options is also BT tool holders. BT holders differ from cat because they are all symmetric and balanced within the rotational axis. BT toolholders contain the same standards of taper measures as the NMBT stud threads that use metrics to move.
Hollow shank tooling (HSK) is a new innovation in tooling that is now used and implemented with various types of HSM machines. It is manufactured for quick changes in tooling and also comes in straight shank formats and dovetail formatting in machinery.
Tool holders features and application widely vary from those who have open coolant flow through the flange or are openly fed by components. Such models, brands, and makes (i.e.. Cat tool holders, BT tool holders, and HSK tool holders) are every bit (no pun intended) of the best examples for this instance. Every one varies in application and interchangeable abilities to adapt to size changes from small to large with the most gap of clearance possible. It is important to understand that every tool holder manufactured is tailored and customized for its specific purpose, task, and job. This makes a vast difference in operational and performance efficiency for use.