CNC SPINDLE :
High Speed Spindles, page 2
Tool Change Methods:
 Spindle motors can be designed with manual fixed collets or automatic tool changers (ATC). Some of the manual fixed-collet systems use a drawbar or spring mechanism to release the tooling. It is always a good idea to see a demonstration of this so you can understand the skill and more importantly the time needed for tool changes. That will undoubtedly get factored into the discussion of whether it makes sense to spend the extra dollars for automated tooling system.
ATC spindles come with tool holders and collets that pick-up and release tooling on the fly with some combination of mechanical fasteners and pressurized air. Your CNC router’s controller must be able to be programmed to drop and reload various cutters, before you consider having this functionality built into the spindle motor. You will also need to have your CNC table designed with a location to mount multiple router bits and holders.
An added bonus is when the spindle comes with a manual override button on the front of the motor that lets you do a tool change manually, … like when you’re standing right in front of the tool... believe me you'll appreciate that at the prototyping stage.
Automated tool change systems should have detection systems for accidental tool ejection. Always ask!
And of course as part of this question, is to ask what type of tool holders this system is designed for (ie. ISO or HSK toolholders, taper size, long or short nose etc). Each tool holder has a maximum tool size and weight it can accept, and a maximum feed speed. It is important to match that to your needs. Often starting a conversation with your tooling guy answers a lot of questions of what the design specs should be for the spindle motor (tool diameters, max rotational speeds, feed speeds, depth of cut etc). We’ll get into a greater discussion in the “tooling” section of this website.
Maintenance:
Bearings should be SEALED CONTACT bearing, and packed with high speed grease. This is the way a high speed CNC spindle motor should arrive at your wood shop and eliminate many of the messy greasing requirements of traditional woodworking machinery.
Ask what the maintenance schedule should be and this might give you some idea on the quality of the motor and whether in fact the bearings are sealed and pre-lubricated. This, in theory at least is supposed to be one of the advantages of using an AC motor rather than a basic wood router. With the later you can get into changing bearings every few months if you use your machine to any great frequency.
High-Speed Spindle Options:
The last thing we’ll suggest before moving onto other hardware components of a CNC router is to let you know that CNC spindle motors can come with a variety of special add-on features that might or might not be appropriate to your needs. Here’s a list of some of these options, just so that you know that they exist…
- Replaceable sensors for front bearing temperature monitoring,
- Single air intake valve for distribution of air to all functions within the spindle motor, including pressurized housing and bearing.
- Surface plating methods for corrosion resistance in nasty environments.
- Offset spindle nose so that tooling can get closer to the edges of the raw material, at least on one side.
- Tool holders and collets, can sometimes be part of the package as well and become a significant part of the price negotiation. Quite often you can get them to through in a number of holders and collets as freebies. At $100 each this really helps.
So that brings us to the end of this particular section on the various CNC spindle motor options and the knowledge you might want to consider if making a CNC wood router or maybe even when selecting what components you want on board for a machine you’re considering buying.
<< back to All about CNC SPINDLE MOTORS
| 