Engraving Fixture Design

[adbuch]

Does anyone have any ideas about a fixture that would hold painted parts for engraving on the plasma table? I was recently asked this question and here was my response.

"I've got some ideas about a fixture plate to hold parts that are already painted for engraving. I would probably either go with electro magnets or tapped holes for hold down clamps. This would be using a flat piece of aluminum tooling plate or flat piece of steel plate - maybe 1/4" to 3/8" in thickness.

Either way, you will probably need to engrave witness marks at either end of your part before you paint it. That way you will have 2 reference points for alignment. The witness marks can be part of the engraved design - so that when you come back after painting you will just engrave over them while you engrave the entire design."

I am interested to find out what methods others may have used.

Thanks,
David

[Fastyankee]

I was thinking of counter sinking several magnets into a piece of aluminum plate and Having a reference marks on the plate that some how correlate with the part I want to scribe. I want to be able to cut a project paint it and than scribe it. Still brain storming on it.
Definitely looking for any input on this on how others are achieving this.

[acourtjester]

What was the tool they wanted to use for engraving. I have a jig I use on my spoil board when I convert my table to router work. And just use a simple G-code to move away from the home position. This method only works it you have homing location switches. I also use on the laser table I have, home at start up then move the X and Y to you jig starting point and zero the DROs. On the laser it is called "set origin". after each engrave action it move back to the origin position to start the next operation. This works for both SheetCam X0 Y0 G-code start and lightburn origin. I also have a laser crosshair on the plasma table to set a start position then zero out the X and Y DRO's. The jig is just used to keep the object oriented with the X and Y path.

[adbuch]

What was the tool they wanted to use for engraving. I have a jig I use on my spoil board when I convert my table to router work. And just use a simple G-code to move away from the home position. This method only works it you have homing location switches. I also use on the laser table I have, home at start up then move the X and Y to you jig starting point and zero the DROs. On the laser it is called "set origin". after each engrave action it move back to the origin position to start the next operation. This works for both SheetCam X0 Y0 G-code start and lightburn origin. I also have a laser crosshair on the plasma table to set a start position then zero out the X and Y DRO's. The jig is just used to keep the object oriented with the X and Y path.

Tom - in this case the engraving would done on a cnc plasma table using an air scribe. He wants to be able to position painted parts back onto the table for engraving using a mounting arrangement (fixture) that will hold the part down without scratching the paint and allow alignment of the part with the engraving tool path file.

I have a setup in my shop using one of my Avid CNC router tables where I have built a mount for using air scribes (engravers) as well as the EasyScriber. These mount to a bracket in front of the spindle. My spoilboard is made from MDF with slots for T-nuts and hold down clamps.

When I am engraving smaller bare metal parts, I simply tape them down to the flat aluminum sheet as shown in the photos. If I had larger painted pieces, then I could use the T-slots in my spoil board along with some low profile non-marring clamps.

David

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