PEI print bed surface experiments

[Nylocke]

You may have to bump the temp 5-10 degrees if you can, or wait for the temp of the PEI to equalize with the temp the thermistor is reading. The PEI is an insulator after all

[teoman]

Bed was on for 2 hours before.

But i will look in to it. If it is an insulator it will be heavily affected by drafts.

[artexmg]

Still no joy.

I have recalibrated the printer. Have lightly sanded the pei. I wipe the bed with isopropyl alcohol before a print. Initially it seems to put on a nice thick bead but towards the end of the print or for sections with a 4 -5 mm^2 footprint it just lets go.

Printing with ABS. Abs temps 217, 225, 232. Bed temps 90 and 100.

Any other ideas?

For me, it works very well IF the first layer is very thin, around 0.15 - 0.2mm max.

So, I have to decrease the % of the first layer OR reduce it, depending of the layer height. Other than that, nothing special.

[teoman]

Why would a thin layer work better?

My first layer is I think about 0.35, and i even tried %150 first layer extrusion. I can see that the filament is well extruded and has a nice and thick extrusion that covers the PEI well. But after some time it just seems to let go for some reason. I will try enclosing the printer if i can make it to ikea this evening.

[artexmg]

Why would a thin layer work better?

My first layer is I think about 0.35, and i even tried %150 first layer extrusion. I can see that the filament is well extruded and has a nice and thick extrusion that covers the PEI well. But after some time it just seems to let go for some reason. I will try enclosing the printer if i can make it to ikea this evening.

This is a very good question. See, at the beginning I started always using 150 or 200% thickness in the first layer. However, I noticed that, depending on the layer height, it could have poor adherence. For instance, for a 0.35 if I used 150% I will get a bad adherence. But, if I were printing at 0.1, then a 200% will produce a good adherence. My conclusion is that there should be a range in the thickness where the adherence is optimal. Other think is, lower the first layer, less room to errors in the first layer that later would arise.

Of course, all this is empirical. No time to run experiments!

Then, when I started using Simplify 3D, I realized that they have, indeed, a first layer % set to 90%.

Enclosing the printer would, as well, improve adherence of course.

[teoman]

Cupboard picked up from ikea junk section. Dimensions verified by guanu. Heading home.

[teoman]

Still no joy. Fiddled with the initial layer settings.

have not installed in to cupboard yet. But it is in a draft free mini room.

[artexmg]

[Nylocke]

I've been printing on a raft because of issues with my printer moving level. The fatter extrusion doesn't stick quite as well, but it does stick snug enough for me to have to pry it off with a razor blade and putty knife. If I get it level enough in an area (and the print is confined to that area) it sticks very nicely with no warping, period.

I have had issue with PLA though, the one try I did with it I couldnt get it to stick at 60, and at 70 it didnt very well and the parts were above their TG (pretty soft). I had to do some Bridge/ABS printing for jobs, so I couldnt try any more PLA printing. Maybe if I try again it would work better...

[teoman]

Being almost at a complete loss, i bumped the temperature up to 115 degs, (it is unable to keep it at that, so more like 111-112). Seems to be holding now.

Will diagnose at the end of the print if it is really sticking on or i am just lucky for this time.

I shall be getting a 18V 30A power supply for the printer. That should enable me to keep the bed at constant temperature.

(The Rambo is rated at 30V all round) would there be a problem supplying 18V to all of the inputs? Or is that just a bad idea?

[nitewatchman]

Is the temperature being measured by the heat bed internal thermistor or an external device. You 115 degrees may be lower than you think.

I run my PEI at 105C (surface measured) for ABS. Adhesion has not been a big issue as long as it PEI is kept clean. I wipe down frequently with Acetone to clean and remove any ABS residue.

[teoman]

Thank you.

Temp data is obtained from the lcd. It is probably not accurate. But I prefer to do my calibrations this way. 115 or whatever temperature is just a parameter I have to tune. It does create a problem exchanging information though.

[Generic Default]

I have to wipe mine from time to time too. I use isopropyl, but I should switch to acetone because it cleans ABS better. Cleaning is mostly to remove dust and particles that settle on the PEI surface. If your prints aren't sticking at all to PEI, clean it then hairspray it.

The temperature that anyone reports can easily be 5% over or under depending on the type of thermistor and setup. People may say something prints perfectly at 230C and looks terrible at 235C, but only difference in temperature is accurate. Plus most of us have glass beds that have a huge thermal gradient. Mine is 5 degrees too hot in the center and 40 degrees to cold on the edges!

[teoman]

I am getting acceptable adhesion now. Have to slow down the print for small parts to prevent corner lift, but all seems good now.

I have an aluminum plate on order waiting for it to arrive.
I really liked the alcohol wipes that i got. I now found some acetone wipes. I will report once I get them to see how they work.
http://www.banggood.com/200Pcs-Nail-Pol ... 87993.html

[teoman]

I suspect I am not reaching temp. Or there are wild fluctuations. And the fact that the sensor is just under where the nozzle visits most heats up the sensor. Then the PID cuts back the power and the reset of the bed ends up colder.

I now have a 4mm Al plate under it. 31cm diameter. Fits perfectly.

I found a fotek relay for 6 usd and its heatsink for 3 usd. They are also on the way. A 24V 20A power supply is also on the way. When they arrive I shall install them.

[mkx]

Wait... I am confused. Is glass necessary?

as in heater -> Alum. plate -> 3M 468MP strips -> PEI

or Heater -> alum. plate -> glass -> PEI

for printing something like ABS?

[teoman]

I had asked the same question a few pages back on this thread, you can look at the answers there.

[BONE]

Looking for PEI sheets on Mcmaster. I thought I heard of people order from there, but I'm not finding. Does anyone have a Mcmaster P/N for 12x12 sheet of PEI from Mcmaster. If I can't find it on Mcmaster, I know it's over on Amazon.

Mcmaster has Polyimide, which is Kapton, but no what I'm looking for.

[Mac The Knife]

High-Strength Electrical Insulating Ultem PEI

Color: Semi-clear amber
Temperature Range: -20° to 335° F
Tensile Strength: Excellent
Impact Strength: Poor
http://www.mcmaster.com/#8685k43/=uzu08o

[BONE]

High-Strength Electrical Insulating Ultem PEI

Color: Semi-clear amber
Temperature Range: -20° to 335° F
Tensile Strength: Excellent
Impact Strength: Poor
http://www.mcmaster.com/#8685k43/=uzu08o

Awesome! I only went down to the P's in the material list, forgot about the Ultem part. Thanks!

[lightninjay]

I don't mean to throw anybody into a rage fit or anything by posting non-PEI stick methods in this thread, but has anyone ever just tried throwing a nice layer of "Aussie Mega Hold" hairspray (shown here) on their glass plate, letting it dry, then hitting it build-manual style, by putting purple disappearing elmer's glue on it?

It's what I do and I never have problems with curling or bed adhesion with either PLA or ABS...

I also attribute a great deal of it to the draft protection of my shower curtain enclosure.

[mkx]

I currently use hairspray and its amazing, but if I can move to something where I don't have to apply anything to the bed, I'm inclined to try it out

[Generic Default]

Hairspray on glass works pretty well, but PEI gives a better surface finish and releases its grip on the part once it cools down. I also noticed recently that PEI + glue stick holds nylon down a lot better than glass and glue stick. Not as good as a heated chamber, but it's a noticeable improvement.

[mkx]

Hairspray on glass works pretty well, but PEI gives a better surface finish and releases its grip on the part once it cools down. I also noticed recently that PEI + glue stick holds nylon down a lot better than glass and glue stick. Not as good as a heated chamber, but it's a noticeable improvement.

Do you need to use gluestick to hold down nylon? Or is it just extra grip? PEI + Heated Chamber should be enough to avoid using a gluestick?

[teoman]

Hairspray on glass works pretty well, but PEI gives a better surface finish and releases its grip on the part once it cools down. I also noticed recently that PEI + glue stick holds nylon down a lot better than glass and glue stick. Not as good as a heated chamber, but it's a noticeable improvement.

By saying not as good as heated chamber do you mean that with a heated chamber gluestick is not needed?