Engraving and uneven surfaces

Hi,

I have gone from a manual engraving machine to a DIY CNC (Zen Toolworks) thinking the advantages would be huge, however, I'm beginning to wonder!! It seems that the CNC machine has to be so precise for engraving it is almost impossible :)

I am slowly putting it all together, got the Dremel mounted now but having issues with the writing skipping some areas and some areas quite deep. All in all quite terrible!

Has anyone experienced this or got any tips? I am guessing it is due to the table being uneven? Please help, I'll listen to anything you have to say!

Many thanks.

You need to surface the table to make it parallel to your router.

I dont know what your bed is made from but if it can be machined you should run a large straight bit or endmill over the bed surface and even it up.

OK, many thanks, simple as that? Phew, I was wondering if I had made a big mistake.

I have a piece of wood for the base, will get on with that over the weekend. Is there a program to do this, or just manually?

Rgds.

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Originally Posted by phatjap

OK, many thanks, simple as that? Phew, I was wondering if I had made a big mistake.

I have a piece of wood for the base, will get on with that over the weekend. Is there a program to do this, or just manually?

Rgds.

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Well, as long as your machine rails are not also warped. I dont know the details of your machine, but surfacing the table should help out a lot.

You will have to make up a program yourself, I did mine in Vcarve and it took no time at all.

You have to specify your table size, and how much material to take off. I suppose you could do it manually as long as you have your limits set.

As others have said you need to surface the your table or work base. If you are still having problems then perhaps your work piece is not planed/face jointed properly. If that is the case you can surface your work piece with your machine and everything should be fine. Yeah, for accurate and highly detailed engravings, greater care must be taken to insure that your work piece is flat and squared up properly.

On a side note, Dremels aren't exactly the most accurate choice for spindles, and generally have quite a bit of runout. Just something to consider.

another important thing I have seen is that you need a spindle that has give in it so when you are working on a piece that is not entirely flat the spindle will lift up over that and still leave a fairly even engraving. some I have talked to say they get around this by putting something that will squish down but give enough resistance for the depth of cut they want from their engraver.

Hello,
Another thing to consider is some form of spring loaded engraving tool holder to allow the tool to follow the surface of the part. There are some available to purchase but with a little effort you can fabricate one that will work very well.
Just another suggestion to help with the problem you have mentioned here.
Regards,

Hi and thanks for your input.

I'm currently doing a design for a spring loaded tool holder which is a mix of some designs I've seen on here but specifically for a small machine. 2 linc don't go down to 3 or 4 mmm sizes. I'm talking to a work shop at the moment to get a prototype made.

Lets see what happens.

Cheers.