Warping Irony...

[wirlybird]

Ok, so PEI. Any particular brand and place to get? How does it work over glass? I am thinking to try it on a glass plate I use so the whole thing can be removable.

[ShadowX]

You may get a reading, but you don’t know if the reading is accurate. The thermocouple thermometers are extremely accurate. I have four different meters and they all read withing .5 degrees difference without any calibration.

[ShadowX]

If you are trying to detect a temperature on a relatively small area, you will not be able to accurately focus on a small area with most IR sensors. I tape the thermocouple specifically next to the nozzle under the hot end block and get accurate results. Sometimes reflective surfaces like glass or aluminum does not provide good results due to the emissivity of the material.

[jfield]

This what I have, not the cheapest either but works very good:

http://www.dx.com/p/tes-1300-2-0-lcd-digital-thermometer-deep-grey-1-x-9v-006p-153128#.WAuKJCRvXoc

And the probe:

http://www.dx.com/p/k-type-surface-temperature-probe-3933#.WAuKgSRvXoc

I was able to verify that my bed has pretty even heat.

[ShadowX]

I have these two meters:

https://www.aliexpress.com/item/Professional-LCD-Display-Digital-Wireless-Thermometer-With-K-type-Thermocouple-Temperature-Meter-With-Data-Hold-Logging/32715243577.html?spm=2114.01010208.3.225.6cJGja&ws\_ab\_test=searchweb0\_0,searchweb201602\_2\_10065\_10068\_10069\_10084\_10083\_10017\_10080\_10082\_10081\_10060\_10061\_10062\_10056\_10055\_10054\_10059\_10078\_10079\_10073\_10070\_421\_420\_10052\_10053\_10050\_10051,searchweb201603\_1&btsid=2e1c2b8d-68e8-45a7-ad5d-842e555928bb

And:

https://www.aliexpress.com/item/Handheld-Digital-4-Channel-Thermometer-High-Precision-Temperature-Meter-K-Type-Thermocouple-Sensor-200-1372Degrees-328/32610758004.html?spm=2114.01010208.3.18.EU4wko&ws\_ab\_test=searchweb0\_0,searchweb201602\_2\_10065\_10068\_10069\_10084\_10083\_10017\_10080\_10082\_10081\_10060\_10061\_10062\_10056\_10055\_10054\_10059\_10078\_10079\_10073\_10070\_421\_420\_10052\_10053\_10050\_10051,searchweb201603\_1&btsid=f49f30e3-b2e2-44c7-92ca-f8cbf18e1b8f

I have two other fluke meters, but they are very expensive and provides the same reading as these two meters.

[Nebbian]

A few 3D places stock it, and you can also get it from Amazon. It doesn’t really matter what thickness (thinner is cheaper). You also need a sheet of 3M 468MP adhesive to stick it down.
https://www.amazon.com/dp/B0013HQ7B0/ref=biss\_dp\_t\_asn

[LarryG]

I was exactly in your shoes - printing PLA and ABS and nothing stuck properly. Then i had to disassemble the print bed for an unrelated reason, and discovered that the power cable for the heated bed was being kinked and was clinging on only a few strands. I re-stripped the wire and resoldered it. Now it works with no problems whatsoever.

my two bits: test your bed temperature, check your PCB connectors and wire connections

If that’s not your problem, get a PEI surface. PEI is absolutely amazing for ABS.

[ShadowX]

If you have a heated bed, look into getting a PEI sheet and stick it onto the glass. No more glues, no more fuss with cleaning surface. The parts stick down to the bed and will not let go. Only way to have it release is to let the bed cool down and the part pops right off. I literally wipe the surface with isopropyl alcohol and I’m ready to print. When its done, I turn on a small fan to blow on the part and wait until the bed cools down and the part comes off easily. You can speed it up by spraying some alcohol to help cool it down quicker. I used to take the print out and put into freezer. Now, I spray, wait about 5 minutes to let it soak in and the part comes out like butter. The excess alcohol on the bed, I just use it to clean the surface and I’m ready for next print.

[ShadowX]

I don’t know how big your printer bed is, but here is a link to a 12" x 24" x 0.032" thick sheet of PEI. You don’t want it too thick since the thicker sheets are more expensive and its not flat. The .032 thick sheets are perfect since you get decent thermal transfer and its thick enough to be durable. You can cut the material to fit a round bed with a sheet metal shear or a heavy duty scissor. Note, the size of the sheet is usually about 1/4 smaller than the stated size. My sheets came in at around 11.75" x 23.75".

Just use the 3M double sided tape to mount it down. I find it easier to put the sheet on the PEI first and carefully lay it down on the bed starting from one corner. Work slowly since if you screw up, the 3M tape is a pain to remove. It will change how you print parts on a 3D printer forever.

No more worries about glue or print bed tape. One thing you do have to watch out is the sheet is soft. You have to make sure the bed height is set right or if you go too deep, you can gouge the surface or leave an imprint. All my prints have a faint outline of 20mm cube on the bottom now (LOL). I had a bad day and didn’t pay attention when I started the print. At least now I have a reference point under the part to know the part size.

PEI sheet

https://www.amazon.com/dp/B0013HJBA4/ref=biss\_dp\_t\_asn

3M Adhesive backing tape:
https://www.amazon.com/TapeCase-squares-Converted-Adhesive-Transfer/dp/B007Y7D5NQ/ref=pd\_cart\_rp\_1\_2?\_encoding=UTF8&psc=1&refRID=NFJEA4K1Y5PR5Y6TR7FM

[wirlybird]

Thanks, I’ll check it out. I have been holding off due to cost since hair spray works pretty good overall. Just trying glue on ABS for the first time. First print was promising until a power blip killed the print!! Go figure!

[ShadowX]

Its actually not that bad in terms of cost. For me it was under $45 and it completely changed how I print. I used hair spray before and now I have two full cans collecting dust. The only thing I buy now is 90% pure isopropyl Alcohol from Walmart. I use it to clean the surface and to cool the part after a print. I can’t imagine a better surface. I tried FR4 based solution like PrintBite, but I was not impressed with the holding power. It holds well at temperature and the part comes off when the bed cools down. However, I still had issues with lifting on corners on small and large parts. I don’t trust it to hold my parts especially for long prints. I have full trust in PEI since there is no way for me to take the part off without damaging the bed when its heated. Once it cools down, you can pop the part right off with no effort. The only issue I have with PEI is that its transparent to IR light, so I have to coat it with black paint in order to use my IR height sensor. Other than that, its awesome.

[wirlybird]

Sounds good. I have some stubborn ABS parts that are large and a lot of infill (still tinkering on that) that love to lift at the corners after several hours.

From what I have read on Printbite it is not great with ABS so I wasn’t going to try it.

[Iceman24k]

you can also adjust the infill pattern to help mitigate this problem…

also I swear and attest to the glue stick on glass or mirror tiles…

also but not as good as glass,… polycarbonate sheet is cheap…

[cobnut]

Just a quick update. I’m getting reliable good results with the blue tape now. Getting those results seems to be mostly about the z-height of the first layer. I’m still calibrating the bed to the glass surface so the blue tape reduces the gap. Print with too small a first layer and there isn’t enough material laid down to form a good bond for the next layer (and you get all sorts of uneven blobs). Print with too large a first layer and the ABS doesn’t adhere well to the tape.

I’ve done half a dozen prints now where there was no warp and in all but one the tape came away cleanly from the model. In the one case where it became stuck to the model (this may have been because I allowed it to cool right down to cold room temp, about 11C overnight), it was easily removed after soaking in warm soapy water.

The prints are still sticking quite firmly to the bed under the tape so need careful removal with a scraper but they’re not “welded” to it like they were with my first attempts with this tape.

So, in summary, for me it seems to be:

1. Use the right blue tape. I’m using the 3M 55mm wide version from Amazon.

2. Warm the bed before applying the tape (to about 65C so it won’t burn you). Applying the tape to a cold bed means you get gaps between the tape strips as the bed expands (and possibly reduces the tape adhesion).

3. Get your first layer height right. I can’t give any examples because I suspect the “right” height will vary from printer to printer, material to material, but essentially if the nozzle is too close to the bed/tape you get a poor first layer and/or the tape welds itself into the print and to the bed, if it’s too far away it doesn’t stick well (to either the bed or the model).

The PEI bed sounds interesting, and I might well give that a go as well. Although the tape is working, it adds time and “fuss” to the print process I’d rather not have (and is of course an ongoing expense, not a one-off, albeit quite a low one).

[wirlybird]

I should be trying the PEI this weekend. It is supposed to get here tomorrow. I am also going to run another glues stick on glass test. The last one was going good until power interrupted the print!

[wirlybird]

I was doing a glue stick test and it was going good until power killed the print. Going to try another starting tonight. I had a lot of infill on my part 50% for strength. It is two pieces that bolt around a pipe like a clamp/bracket. I think if I do even more shells I can reduce infill since many shell layers around the bolt holes should give good crush strength.

[wirlybird]

Well, this whole PEI experiment was a huge waste of money. I haven’t even been able to print with it. As the bed gets up to temp for ABS (100c) the PEI starts to curl and peel up all around the edges. The interesting this is the PEI sheet was perfectly flat as I installed it.

[Nebbian]

What adhesive did you use to stick it down? Did you really clamp it down when installing?

[ShadowX]

You need to install with the 3M 468MP double sided tape. Other types of adhesive can not handle the temperature without delamination. You can’t install the sheets on top and use clips either. It has to be bonded down to the glass with the tape to work. What type of bed surface are you using? Glass? Did you verify the surfaces are clean before you stuck the PEI sheet on it and verified all the bubbles are removed?

Here is another thing to try. Heat up the bed and put another sheet of glass over it and apply some weight over the bed to get the sheet to stick down. You will still need to put in clips along the edge to hold the glass plate down to the bed surface and it would go over the PEI sheets.

[ShadowX]