I have my first application for digitizing a hand made model so that I can cnc machine a mold for it. I'm just wondering what is the most economical method, or equipment that I would need to purchase to do this.

I have a cnc mill with a Shadow controller on it, but it is pretty much a black box, ie., I cannot interface any kind of a probe with it directly. So, I could use a touch probe and manually record positions. The part is not very complex, but it does have a free flowing form that I think could be captured quite well with cubic B spline curves through points maybe on a 1/4 inch grid.

I have no experience with such procedures, and I'd appreciate hearing any advice and tips on doing this whole procedure. I am not against spending a bit of money to get set up a bit better, but at present, demand for this type of work is extremely low, so I cannot justify buying a Faroarm, much as I would like to.

Thanks in advance for your replies.

Hu,
Do you have a CMM?
If you do, there is software out there that you can use to collect a "cloud" of points from you model then import them into you cad system.

The other option would be to sub the work out to someone in your area.

I have a small CMM that I use from time to time like this , but other times I will send the model out to have it done.

I don't do much work like this, so if I had it to do over, I probably wouldn't have spent the money on the software to do it.
I would sub the work out to someone who makes a living at it.

JMO
Ward

Thanks for the reply, Ward.

Naturally, there is nobody in my area who can do this, so I'd have to be the first.

I was looking at the Microscribe 3d digitizer arm. I wonder if .009" accuracy is "smooth enough" to make a good representation of a fairly simple, but rounded model. Would it end up looking dimpled?

Murray

Hu,
Had an another idea. Do you have a 3 axis dro?

I know that Anilam DRO's have a way to output data to a computer. IE: use a touch probe and then output the cordinates to computer.

I don't know if other brands of dro's will do this, but I'm sure some of them would.

Even if you only had a 2 axis you could lock in z and take some points then move z dn and take another cloud.

Just a thought. Might be worth a call to your dro guy.

Good luck,
Ward

Hey Hu,

Do you have a picture of it? That would help in coming up with "cost effective" ways to digitize it.

If it's got constant radii curves, then touching can work, it's just time consuming. I made a ball nose "touch probe" from a piece of carbide blank and used the usual rolling paper method. I then took the points from the radius ends and used them in a demo version of Bobcad to create a drawing. It took a while, but it worked. The things we do when we don't have a budget......

Adam

I let that project go. I'm just not technically ready for it yet. What I need to do is re-re-retrofit one of my mills with another pc based cnc (like my lathe project, using camsoftcorp). With their pc based cnc, I could easily grab the digitising data from a probe on my machine, because I could write the logic to do it.

There's nothing that beats a cnc controller interface that you can write logic for to suit yourself. :)

Beleave it or not in the past when needed I have use a bridgport mill with a read out and have taken point postions useing the read out and touching the part with hand made say .250 probe.

Write down each point and punch it into the cad system and build from there.

I have done this on molds and golf clubs.

Max NC has a really nice digitizing probe taht works with their systm. Don't know if will work with any oter controllers but it is worth trying to talk to them
Regards,
Sorin

DeakCNC is also a nice package for digitizing and their digitizing probes are a really nice price as well.