SoliForum - 3D Printing Community — Hand lapping the print bed

Re: Hand lapping the print bed

2012-12-11T06:02:56Z

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.

Re: Hand lapping the print bed

2012-12-10T05:55:22Z

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

Re: Hand lapping the print bed

2012-12-10T05:17:16Z

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.

Re: Hand lapping the print bed

2012-12-10T03:53:05Z

!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.

Re: Hand lapping the print bed

2012-12-10T00:57:33Z

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.

Re: Hand lapping the print bed

2012-12-09T20:03:08Z

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.

Re: Hand lapping the print bed

2012-12-09T16:20:02Z

Pictures?

Hand lapping the print bed

2012-12-09T16:00:16Z

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.