Low End CNC Machines as Motion Control Platforms in Manufacturing Cells

I had the pleasure of having lunch with Andy Grevstad from Tormach recently, during his visit to the Bay Area for the Maker Faire. Andy, who is quite the gentleman with an inexhaustible passion and knowledge for CNC-related matters, is no stranger to many. During our conversation, we somehow veered into discussing how many people use their Tormach Mills for turning, which led to me suggesting that Tormach should design the lathe spindle in such a way that it allows for easy mounting of various accessories. These should be set up beside the spindle in an accurate and repeatable fashion. I envisaged something like a dowel pin plus bolt set-up on the surface around the actual spindle. Upon hearing this, Andy took a moment to contemplate before making an insightful comment:

You'd be surprised at how many people are using Tormach's as general purpose motion platforms.

Turns out folks will purchase a Tormach mill and turn it into a dedicated machine to do something or other as part of a Manufacturing Cell.  I can't really talk about any of the specific examples he gave as I'm sure it is Tormach's privelage to talk about how their customers use their products.  But it is an interesting topic, and one that Tormach has been pursuing and augmenting for quite a while.  Consider some of the products they offer:

• Touch Probe:  Let's you turn a Tormach into a CMM-style precision measuring machine.
• CNC Scanner:  Need to take a high resolution microscopic picture of something?  Stick one of these in a Tormach and you're there.  I could imagine needing to do some kind of inspection in a manufacturing cell and having a Tormach with Scanner all set up to do that as the parts pass through.  With the right g-code, you can position the camera's view frame in exactly the right spot on a big grid of parts and let an operator click to move to the next part when he is satisfied with the inspection.
• Duality Lathe:  Lots of big-time manufacturers have found it is convenient to be able to perform turning operations on mills.  See for example my article on the RAMTIC manufacturing process.
• Tormach's Injection Molding System:  This is a light duty injection molding system that takes advantages of the CNC Motion capability of a Tormach Mill.
• Tormach's 4th Axis:  4-axis motion can be extremely helpful for many applications.

This list could go on for quite a while.  I've got a machinist friend in Hawaii who likes to say that if he can control it with g-code, he can make it do anything, and he is very good at automating processes in that way.

I still like the idea of a precision repeatable mounting area on the spindle for things that you don't want to expose the spindle bearing to.  For example, you could mount a broach there, or gang tooling for a lathe arrangement.  The other alternative is special toolholders that let you do various things.  I can see lots of applications for a machine used like this:

• Engraving:  True, this is nearly milling, but imagine outfitting a mill like the Tormach with a high speed engraving spindle.  Finish the parts, whatever they may be, and this is one of the final stops in the manufacturing cell to do some custom engraving.
• 3D Printing Extruder Head:  Seems like a natural.  Who will make one that fits into a Toolchanger?
• Airbrush Attachment:  I have a couple of customers who use GW Editor to program g-codes to apply various special liquids to parts as a stage of manufacturing.  I think one is applying a special heat proofing paint and another is applying anti-seize to some threads.
• Pick and Place Assembly ‘Bots:  What has to go onto the spindle to let your mill do pick and place assembly?  I'm talking about grabbing a bolt and tightening it up.  Or, pulling parts off a pallet and sticking them into a bin.
• Deburring:  Lots of processes need deburring.  The industry makes all sorts of special brushes that are stainless bristles or that have abrasives to do deburring.
• Inspection:  We touched on this one.  For a lot of inspection jobs you don't necessarily need CMM-quality accuracy.  What you can get with a touch probe on a low-end mill will do just fine and can be automated.
• Glue/Caulk:  All sorts of useful things are available in tubes suitable for Caulking Guns.

NASA Uses a Tormach to Wind Special Coils

A Tormach Mill was used to help wind a special component for NASA’s Piper mission:

Creating these intricate arrays of tiny wire filaments was obviously a job that needed some automation, if only to keep the precision high and the manual boredom to a minimum.  The gizmo is a polarizing filter for the microwave spectrum.  Photographers have all seen these for visible light, but this is what one looks like for the microwave end of the world.

More details over on the Tormach blog!

Conclusion

So the next time you need to make a lot of some kind of part, try thinking about your mill as a general purpose 3 or 4 axis motion control system rather than as a milling machine.  Go through our Manufacturing Workflow, relate that to your operations, and think about what you could automate with a low-end mill as a component.  You might just find that relatively few changes to the mill are needed to get a lot of value out of it.  Considering what these machines cost, it's pretty easy to see an ROI.