PEI print bed surface experiments

[mhackney]

So there is something wrong. PEI will stick to ABS without any additives. I suspect silicone contamination. I had that problem too. Clean well with acetone. If that doesn't work, use 1500 grit or finer sandpaper and sand the surface. This will create a clean surface with very small scratches - so fine you won't see them on the bed or prints.

I am a bit concerned/curious about the color of your plate though. Literally every piece of PEI I've bought and seen have been amberish. I use a fair amount of it for special components in my fly fishing reels so I've seen quite a bit. I've never seen crystal clear like that. Maybe post a link to the site where you purchased it?

[JohnStack]

It's the .03 w/ adhesive backing from CS Hyde, it does have a slight yellowish hue. The surface was cleaned with both acetone and alcohol. The cloudiness happened before I went down the silicon route as well.

(Silicon from underneath the PEI?)

I've had edge curl every single time I've printed this damned thing.

I'll try sanding it down w/ 1500 grit.

Here it is at 55 / 218 layers.

[Eaglezsoar]

It's the .03 w/ adhesive backing from CS Hyde, it does have a slight yellowish hue. The surface was cleaned with both acetone and alcohol. The cloudiness happened before I went down the silicon route as well.

(Silicon from underneath the PEI?)

I've had edge curl every single time I've printed this damned thing.

I'll try sanding it down w/ 1500 grit.

Here it is at 55 / 218 layers.

20140409_125126.jpg

John, I know that you know what you are doing but is there any chance that Z0 is not close enough to the bed?

[JohnStack]

Thanks.

Sanded it with 1,500 grit. Recalibrated just in case. Just cancelled #6 w/ worse curl than before (no glue stick)

I've always had problems with that particular area of the bed anyway. I'm going to chaulk it up to that. I will not be going to the effort of borrowing my friend's Flir to see what's going on with the bed...I've used a heat probe and it's within 10% from what I see.

Done for the day, need to pick up some PLA for a different project to print on the Robo3D. It's my goto PLA printer.

Try Try Try...

[mhackney]

I really suspect your PEI then. I can't tell you how well PLA and ABS sticks to this stuff and there are lots of testimonials to that effect.

Send me your STL and I'll demonstrate how well it prints on PEI!

[rampeh]

Amazon was out of 0.03" PEI so I opted for 0.06". Adhered with the adhesive tape and initial tests seem positive! My first couple of prints stuck like magic!

My sheet came with both sides glossy though, and i much prefer the natural matte finish. Does anyone have any guess how I could put a matte finish on it? My other bed is sand blasted borosilicate, which gives a beautiful finish but is a nightmare to get anything stuck to (I was hoping it would help adhesion but it is no better than gloss glass).

Could sandblasting the PEI improve the finish? How about just hand sanding with fine grit (Although i'd be worried about sanding it unevenly). I have never worked with PEI before.

[mhackney]

Great. Yes, use 1500 grit sandpaper and lightly sand he entire surface. It will raise a bit of dust but leave a nice matte surface. I wouldn't risk sandblasting, too abrasive. Soda blasting maybe but try the 1500 grit first. The material is dense and the grit is very fine, you really can't sand it unevenly.

[rampeh]

I'm kicking myself for not saving my offcuts for testing sanding!

[mhackney]

Well, I did save my offcuts - as friend recently called me a Pack Rat . Came in handy to test this.

Cheers,
Michael

[Skupitup]

I would like to use a PEI bed for my printer, but would like the surface to be removable. Cost aside, is there anything wrong about using a sheet of PEI 3/32 thick from mcmastercarr and just using binder clips to hold it down? or is there still risk of the bed bowing?

[mhackney]

Yes, it will not be stiff enough and will curl and bulge up. Your best option - and what I did - was affix the .03" PEI to one side of your borosilicate build plate. Then you can flip it over to print on glass and it can be removed.

[Skupitup]

Alright, that was the other option, thanks!

Another question, If I were to muck up and set the height too low causing the extruder to crash, is it going to damage the PEI a lot or can that just be smoothed out with some 1500 grit?

[mhackney]

1500 would not smooth out a divot, it is too fine. That said, I've not had any divots pecked in mine. Be careful when you set up Z=0 and you should be fine. You could just as easily break the borosilicate with a crash so go slowly.

In theory, if the PEI gets mucked up you could peal it off the glass and turn over and re-attach to get a fresh surface.

[Skupitup]

Oh, I wouldn't have expected the 3M tape to be that easy to peel off... I though it was like a one shot done deal

[mhackney]

I have no idea, that's why I said "in theory"! It is very tightly stuck. But I suspect there is a way to remove it if absolutely necessary. Perhaps list an edge and squirt acetone on it, etc. Where there's a will, there's a way.

[JohnStack]

Success.

After many trials with Jetpad's Ezstruder Top Mount (stock, no mickey mouse ears)

Ultimately, I replaced the adhesive-backed PEI with another layer of it. Sanded again with 1,500 grit. Rotated my print (yes, I have a bad spot on my bed), and laid down some glue stick. Ran the print at 75 degrees, slowly, at .25 first layer height.

I tried every combination possible (bold worked for me):

70, 75, 80, 85
glue stick no glue stick
sanding, no sanding
rotating the print
.25, .35 first layer height.
30% speed of 30mm/s after various speed tests.

The last trial was glue stick/no glue stick. I had some curl without so I decided to use it. I got 100% sticking - finally.

Whee! Worth it? It's going on my printer. I think it needs to look good.

[mhackney]

Something is still wrong. You should not need glue stick. That defeats the beauty of PEI - it sticks fantastically without other treatment. Even the sanding was a minor workaround for me because I knew I had silicone contaminating the surface.

[Eaglezsoar]

Success.

After many trials with Jetpad's Ezstruder Top Mount (stock, no mickey mouse ears)

Ultimately, I replaced the adhesive-backed PEI with another layer of it. Sanded again with 1,500 grit. Rotated my print (yes, I have a bad spot on my bed), and laid down some glue stick. Ran the print at 75 degrees, slowly, at .25 first layer height.

I tried every combination possible (bold worked for me):

70, 75, 80, 85
glue stick no glue stick
sanding, no sanding
rotating the print
.25, .35 first layer height.
30% speed of 30mm/s after various speed tests.

The last trial was glue stick/no glue stick. I had some curl without so I decided to use it. I got 100% sticking - finally.

Whee! Worth it? It's going on my printer. I think it needs to look good.

John, what kind of filament are you using that requires a glue stick in addition to the PEI? If it requires a glue stick then what advantage did you gain?

[JohnStack]

I'm using Orange ABS from Seemecnc.

All I know is I tried several prints with the new surface (sanded) and I got edge curl. On this last print, I can slide a piece of paper underneath the flat corner but I'll take it.

I measured bed surface temps. The bad area that I rotated away from reads about 58C. (towards the Y axis)

The area I rotated to (x) reads about 66.

This is, of course with my thermistor on an original Seemecnc bed reading 75C.

I think it's temps. MHackney, you've got an AL spreader. I'm trying to be stock. That spreader makes the difference IMHO.

[mhackney]

A temp gradient might be the culprit. ABS needs about 65° to stick well to PEI. I print a bit higher. Can you set the bed to say 85-90° and see what happens. That might get the minimum temp up above 65° and help out. I think there are folks here printing on PEI attached to glass on the stock Onyx. Perhaps they can pipe in with their experiences?

[bdjohns1]

I'm printing on the thicker PEI taped down with the 3M acrylic adhesive.

I've got my Onyx hooked up to a 24V supply. Parts that have a small contact area, I'm printing at 110C on the bed. Medium sized (80mm-ish), I drop it to 100 or so. Haven't tried a real long part yet.

[mhackney]

You need to tell us what filament you are printing with when you post bed temps! I'm guessing ABS since 110° would melt down PLA.

[bdjohns1]

You'd be correct.

[rampeh]

Great. Yes, use 1500 grit sandpaper and lightly sand he entire surface. It will raise a bit of dust but leave a nice matte surface. I wouldn't risk sandblasting, too abrasive. Soda blasting maybe but try the 1500 grit first. The material is dense and the grit is very fine, you really can't sand it unevenly.

I went to my local hardware shop and they only had up to 1200 grit. Do you think that would be fine enough? I'm not from the US so buying another PEI sheet if i ruin this one is a pricey endeavor!

[Eaglezsoar]

Great. Yes, use 1500 grit sandpaper and lightly sand he entire surface. It will raise a bit of dust but leave a nice matte surface. I wouldn't risk sandblasting, too abrasive. Soda blasting maybe but try the 1500 grit first. The material is dense and the grit is very fine, you really can't sand it unevenly.

I went to my local hardware shop and they only had up to 1200 grit. Do you think that would be fine enough? I'm not from the US so buying another PEI sheet if i ruin this one is a pricey endeavor!

1200 grit should be fine. I would not use anything coarser than that.