Could Taig mill be used for Prototype Molds?

[arich]

I am looking to set up a small plastic part prototyping shop but have minimal space. I was thinking about just getting one of the Taig micro cnc mills. How easy would it be to cut quality finish aluminum molds with one of those? Has anyone been successful doing this? I will be using it to learn on as well, this is part of the reason I want something cheap to start with.

[mgamber]

Yes, with some small modifications. I am in the process of building a TAIG with ballscrews to get rid of any backlash to cut carbon EDM probes that will burn small injection molds. Contact me if you are interested in getting a TAIG setup for CNC.

[arich]

how much are ball screws? also, i wonder how much babysitting is required on a TAIG. do you have to have someone sit there spraying wd-40 while the thing runs for 8 hours? how are chips removed without having cutting fluid or a mist spraying continuously onto the bit?

[mgamber]

Originally Posted by arich how much are ball screws? also, i wonder how much babysitting is required on a TAIG. do you have to have someone sit there spraying wd-40 while the thing runs for 8 hours? how are chips removed without having cutting fluid or a mist spraying continuously onto the bit?

Unfortunately they are rather expensive. We were initially quoted $1000 for just the x and y (which is all you need)

I am trying to get the price down...

I have a coolant system installed on mine (Trico MD1200) that turns on and off via the CNC control.

What controller are you going to use? I can also build you one of these.

[ViperTX]

I believe the Taig that is CNC enabled already has ballscrews and is around $2200. You have to consider the size of mold that you need. So, you'll need to know which plastic injection machine you are planning to use....and most commercial ones require a rather large mold...much larger then the Taig can handle.

If you are "pour casting" when then that's another story.

[mgamber]

Originally Posted by ViperTX I believe the Taig that is CNC enabled already has ballscrews and is around $2200. You have to consider the size of mold that you need. So, you'll need to know which plastic injection machine you are planning to use....and most commercial ones require a rather large mold...much larger then the Taig can handle. If you are "pour casting" when then that's another story.

Boy do I wish the TAIG came with ballscrews! But unfortunately no, they are standard 1/2-20 standard threadform leadscrews.

The size thing is a good point, the taig has an 18" x 3.5" table with 12"x 5.5"y an 6"z travels. Might be fine for the size of the cut in the mold but how big is the mold block?

[arich]

i found a company that makes a tiny injection molding machine just for small cheaply made molds. i figure something like this would be fine for prototypes and even small production runs.

www.morganindustriesinc.com

[arich]

you think i'd be better off going with a higher end CNC mill to begin with rather than going through pains to soup up a TAIG and learn to use that? If I get the TAIG cnc and later decide I want to upgrade then i would have to learn a whole new system over again.

[mgamber]

Originally Posted by arich you think i'd be better off going with a higher end CNC mill to begin with rather than going through pains to soup up a TAIG and learn to use that? If I get the TAIG cnc and later decide I want to upgrade then i would have to learn a whole new system over again.

Maybe.

I DO NOT recommend using the TAIG controller. You are better off adding a controller and steppers or servos to their CNC ready machine. Also use Mach3 software. This is a very good starting point and if you want a better mill later you can move the controller and software over to that machine and it will work almost exactly the same. I build these controllers, contact me if you want a quote.

The problem with the basic TAIG machine is the backlash and not the precision. If you can write the G-code to compensate then the zero-backlash upgrade is not necessary, but for 3-d contouring with extreamly high accuracy, then...

How accurate do you need to be? Can you live with +- .003? The basic TAIG will do that.

[cartertool]

Originally Posted by arich how much are ball screws? also, i wonder how much babysitting is required on a TAIG. do you have to have someone sit there spraying wd-40 while the thing runs for 8 hours? how are chips removed without having cutting fluid or a mist spraying continuously onto the bit?

Most people either rig up a flood or mist cooling system, I use a Kool-Mist running with a timer box that pulses every 5-10 seconds (cuts down on mist in the air), see here:
mist system

I suggest asking questions on the taigtools yahoogroup, you will find most users over there who will be happy to answer your questions and relate their experiences.

For the record:
The Taig has 1/2"-20 lead screws, not ball screws.
The nuts on x and y are adjustable for backlash (z-axis headstock weight takes up backlash), usually you get between .0005 and .003 which is compensated for in software. You do have to stay on top of it but you should be able to work to .001-.002 if you do, and a reasonably competent.

I make some index plates that are usually out no more than .001.

The downside of Taig's screws is that you really can't go much faster than 10-25 ipm, although some users with aftermarket controls do go faster, but for 3D milling it can take a lot of time to make a mold...