[JIM@PROCAST]

HI
I'm new to this forum and the whole world of CNC:drowning:

I make signs from cast metal but obviously the patterns for these are firstly made from wood.

For the past 25 years we have cut all our letters using a band saw and a fret saw cutting letters from about 12 inch down to 1/2 an inch , using wood from 1/8 upto 1/2 an inch
Obviously doing it this is "old skool" and very time consuming.
So I was looking at a machine that is capable of cutting these letters out.

The letters must have a tapered cut on them is this possible with a laser cut or router..

The machine only need to be a desk top one.
Has anyone got any suggestions on what would suit my needs.


Many thanks
JIM

[CNCwill]

Hi,
I was a pattern maker for 25 yrs and used a CNC for 8. To cut draft on a pattern for casting purposes, Use a tapered mill. You can buy them with varied degrees. Depending on the look you're going for 2-3 degrees is plenty to sand mold most castings. I made some very complicated tooling to using CAM software that modeled the draft into the model and then used a ball end mill to contour the shape. Best of luck.

[JIM@PROCAST]

many thanks for the reply
one concern I had was that with a tapered mill is that the internal corners would end up round instead of a point.
Say where the internal upright and diagonal lines meet on a "N"

also can you recommend a suitable machine, or ones to avoid.

[CNCwill]

There are a lot of parameters to consider, most green sand founders want a fillet in a corner, dry sand less but then you need to consider the height of the draw, (how high is the actual letter). I don't know what kind of volume you are talking about or if the signs include contours other than lettering. I'd pretty much need to see a sample of an average design to make other suggestions. As far as brands, I used a Haas VF-2 and cut wood, plastic, aluminum and iron tools with it. I doubt you need something like that so I'm afraid I can't help you there.

[JIM@PROCAST]

most of the signs are one offs a few have 4 made from the same pattern.
like the one here.

[CNCwill]

One option not to be ignored is just using a sharp chisel after cnc work to remove the unwanted fillets. Because I had a tool changer and could let the machine literally work through the night. I could work a tight corner by reducing the size of the endmills to the needed parameters and have some very fine details as a result.