Making panels with own CNC

[davek]

I have been working out how to use the CNC to make panels.
One thing that has me a bit confused is.. (it dont take much) This is how I see it so please edit to put me on the right track

Use white opaque plastic
spray with the appropriate cockpit panel colour

Put in CNC
Watch the magic as its cut out

Now I have a panel with the shape, holes and text
However the edges are white from the shape cut

Now I have to spray the edges with the risk of over spray onto the text.

Or

you cut out the shape,
then paint
then put back in CNC to etch the text. If so it could be difficult lining it up so that it matches.

How do you guys do it?

[Wendy]

The way I do it is...

-cut the panel
-save the position in de router software
-mark the panel position on the table
-paint and let it dry several days
-put the panel back on the table for engraving, but do a round first just above the panel to check if the position is right and adjust if necessary



Regards Wendy

[Jylhami]

Or use a common method of using a jig.
You can first mount a 10"x30" mdf board to your table.
Then have your panel picture and use your CNC code program to make the corner mounting holes deeper. like 20mm (so it cuts about 15mm to the mdf) and use the diameter something equal where you can put a lining tab. After the panel is cut out and painted, just hammer down the 4 pegs and you have a perfect place to drop the panle for engraving.
I use lining tabs used in putting gearbox halves together, they are 5mmx20mm with rounded ends.

[mondo50m]

I paint the panel, let it dry for a couple of days. Put it in the router and do the text and then the cutouts. I went to home depot and had them make me a sample pint of the paint I am using on the panel. Then I paint the edges
with a small brush. I have never been able to get the alignment right if I cut
the panel then paint then engrave. But I am going to try it the way Jylhami is
doing it.

Milt

[Hessel Oosten]

A variant on Jylhami,

Drill holes deeper as stated before in his posting.

Drill them with the size of the endmill shaft you are using (e.g. 1/8 "; 3,175 mm) EVEN if they should larger (see later).
So take a mill where the shaft and millingtip end have the same diameter or if the milling end is smaller mill internal till diameter is the same as the shaft.

It's also possible to drill holes on other places than the mounting holes before e.g. the place of rotary shafts or (later) windows of Korry holes (doesn't matter).

So make the previous mentioned object at this moment *NOT* the right shape, but only drill the mentioned holes in that place.

After removing the nearly complete milled panel, use *broken* endmills .... to place in the drilled MDF holes. Remember they have now the same size as the hole.
These endmills are used as guides when putting the panel back after painting.

Now, after fixing the panel these broken mills are removed.
Now the places where they were located can be milled to the right dimensions (e.g. the rotary hole comes now from the prevoius 1/8 " to 6,1 mm).

Another possibility is to put 2 small laths (crossbar ?; don't know the right word) on the MDF.
Mill a small part awy from it in X and Y direction.
You know that you did it e.g. at X = 40,4 and Y = 30,3.
Now you have in the edge of the laths your new exact 0,0 point.
Put the panel in this corner, correct for the millend diameter and your panel is also in place.

Another trick to find exactly the edge of a panel is to put upside down (there we go again.... an broken endmill shaft in the mill (e.g. 1/8"). Go slowly to the panel and when you hear it (contact now some microns) the mill is 1/2 the diameter of the shaft form the panel. very accurate too.
There are for this trick also more sophisticated=expensive instruments.

The NEVER-NEVER-trick is to think, that you can do it with your eyes !!!

Hessel

[davek]

Thanks everyone, some great ideas there, I will give them a go and see which one works best for me and my set up

[CocnutAir]

What type of CNC do you have: machining (router, etc) or laser?

[davek]

Alan I have a Shark CNC http://www.rockler.com/product.cfm?page=19441 with a small Bosch router running the V carve software.

I am having some problems with cutting smooth lines and text at the moment.

The cut outs are no smooth. Seems the router is following the vectors to give a ripple edge in some areas of cuts.

Text is not a single line so it is cutting around the vectors and not in between the lines.

I have adjusted the feed rate and plunge depth making multiple shallow passes, which has improved it a bit but not perfect.

I am sure its just the operator and not the machine. I have been practicing on MDF before I move onto the plastic (which is more expensive)

[CocnutAir]

My experience is with CNC laser.

[riche543]

Hi there take a closer look at your drawings , as i had the same thing untill i really zoomed in on the lettering. What you will most likely see is that the lettering is not made up of one smooth line but many short lines, that you wouldnt normally notice hence the ripple letters. I was able to sort it out using adobe illastrator but do some googling about it. it could be the way the software is drawing your letters etc etc.... Hope this helps ya a bit
Cheers..
Riche