1 Topic by heychris

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Topic: Hand lapping the print bed

All,

In my glass bed addition I took a chance to hand lap the print bed.  It was significantly not flat.  If anyone  is interested, I took a sheet of glass to ensure flatness.  I taped a full sheet of Silcon Carbide sand paper.  Slowly sanded flat.  I started with 120 grit and ended with 600 grit.    My preferred method is to slide left to right until all the scratch marks go that direction, then switch to up/down.  Similarly move up / down until all scratch line up.  Eventually you'll have a mirror finish.

2 Reply by DePartedPrinter

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Re: Hand lapping the print bed

Pictures?

SD2 with E3D, SD Press, Form 1+
Filastruder
NYLON (taulman): http://www.soliforum.com/topic/466/nylon/

3 Reply by Tomek

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Re: Hand lapping the print bed

How thick was your glass? I've found even my cheapo supply is quite flat. At least as flat as any alu stock that isn't specially flat certified.

4 Reply by heychris

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Re: Hand lapping the print bed

I didn't think to take pictures.  It's a pretty easy process.  As long as you take it slow with steady pressure to keep it flat, it's no big deal.

The piece of glass I used was salvaged from a scanner.  It is about 1/8" thick.  I recently aquired a machinists marble slab with flatness certification.   I can't tell the difference between that and a piece of glass.  I've always used glass as a flat surface.  It's pretty accurate.

5 Reply by Tomek

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Re: Hand lapping the print bed

!Oh, heh, you mean, you made the aluminum bed flat.

I was confused, and thought you sanded down the glass plate. Hence, I was quite surprised that it wasn't flat enough for you.


Not a bad method. I didn't realize you could make the aluminum plate flat.

6 Reply by ronsii

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Re: Hand lapping the print bed

Did you do the lapping hot or cold?

If cold does it stay flat when up to temp?

I am curious because I am thinking about just putting glass over my bed and going with that.

7 Reply by devilman2075

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Re: Hand lapping the print bed

Unless your bed is extremely warped and your putting a lot of strain on the glass with clips you should not have any issues putting straight onto bed

8 Reply by heychris

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Re: Hand lapping the print bed

I agree, It's  a bit extreme. 

My inner engineer can't stand using a dial indicator over a surface that hasn't been checked for flatness.  I also think it helps heat transfer to remove any air pockets between the glass and aluminum.  With the unfinished surface I could run my fingernail across the surface and detect bumps.  I ended up spending a fair amount of time sanding as it was quite off.

Also I agree that cold vs warm is important.  I'm hoping the dial indicator will help show me the success.