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an interesting observation I've found...... Mike, after your comment on steel thickness issues, I pulled out my calipers..

My glass is not flat. it's got curves and waves. which I knew all along.
Nor is my PEI. its got ripples.. some .005" +/-
Nor is my bed. (it's WAY out)

Nor can my Orion print flat. Even if the above WERE flat.

Yes, I can get it close. And yes the glass is more flat than the PEI and FAR more flat than the bed.

But at the end of the day, this is not a micro-surgery tool. It's a rapid prototyper, and a crude one at that.

I'm going to pull the trigger on some alum plates, just to see what we come up with in terms of flatness. after my measurements on the glass and PEI, AND considering how phenomenally good the product looks despite those 'bumps', I am really a bit doubtful if it can be that big of a problem.

I think the PEI will go A LONG way to helping with this, because it allows you to set up a platform, get it flat, lock it down, and not change it..

PRIOR to PEI, I was regularly pulling the glass to clean and re-apply Kapton. Then I had to re-orient it, then re-calibrate level in all three directions, then pray the Kapton didn't get f'd up during a print, so I wouldn't have to start all over again.

OrionNOOb, it is all relative, I agree. However, I wanted to share my experience to maybe prevent or minimize your pain! I produced 50 aluminum plates and sold them to Rostock owners last year. The stock was 1/8" and was "darned flat" in sheet form (4' x 4' sheets). These parts were water jet cut and then I drilled and finished them by hand. I checked the flatness with a good steel straight edge on every unit and they all were "darned flat" when they left for their new owners. Then, owners complained about bows in these plates. I ended up refunding everyone who had a warped plate AND I refunded their shipping costs too. Needless to say, I lost a lot of money on the (ad)venture. These plates were 12-3/16" diameter and drilled so they held the Onyx down. I still use mine and it is as flat as I can measure.

I have my Rostock dialed in and I can print the full 11" (or so) calibration print that we use to check. I do have to bring everything up to temperature and let it equilibrate for a good 30 minutes to get consistent/predictable results. Ambient heat and humidity affect it too but I can tell when I print the first layer or that calibration part what needs tweaked and that's what I do. I can usually tweak to get within +/- .1mm in thickness across the entire part. It took me quite a bit of work to get to this level but I frequently print large parts - 8" across and need a pretty flat surface. If the bed is warped or the printer not calibrated properly so there is a variation of greater than .25mm in Z these parts will usually fail because the first layer won't stick properly. That's all I'm trying to say.

My borosilicate is pretty darned flat too. Although I do orient it the same way after removal, I've sometimes rotated it 90° and have no problems and I certainly don't have to recalibrate after removing and reinstalling the glass. Everyone has a different process and setup. I've been very methodical with my machine because I do produce reasonably high precision parts. The fly fishing reel I designed I can print and have a completely functional reel (rotating spool and rotating handle) with no cleanup using a particular spool of PLA that I've dialed in for this. Switch PLA and the tolerances change enough that the spool needs to be reamed to rotate.

Also, I design keeping the layer height in mind and create parts that are an integral number of layers in Z.

mhackney wrote:OrionNOOb, it is all relative, I agree. However, I wanted to share my experience to maybe prevent or minimize your pain! I produced 50 aluminum plates and sold them to Rostock owners last year. The stock was 1/8" and was "darned flat" in sheet form (4' x 4' sheets). These parts were water jet cut and then I drilled and finished them by hand. I checked the flatness with a good steel straight edge on every unit and they all were "darned flat" when they left for their new owners. Then, owners complained about bows in these plates. I ended up refunding everyone who had a warped plate AND I refunded their shipping costs too. Needless to say, I lost a lot of money on the (ad)venture. These plates were 12-3/16" diameter and drilled so they held the Onyx down. I still use mine and it is as flat as I can measure.

I have my Rostock dialed in and I can print the full 11" (or so) calibration print that we use to check. I do have to bring everything up to temperature and let it equilibrate for a good 30 minutes to get consistent/predictable results. Ambient heat and humidity affect it too but I can tell when I print the first layer or that calibration part what needs tweaked and that's what I do. I can usually tweak to get within +/- .1mm in thickness across the entire part. It took me quite a bit of work to get to this level but I frequently print large parts - 8" across and need a pretty flat surface. If the bed is warped or the printer not calibrated properly so there is a variation of greater than .25mm in Z these parts will usually fail because the first layer won't stick properly. That's all I'm trying to say.

My borosilicate is pretty darned flat too. Although I do orient it the same way after removal, I've sometimes rotated it 90° and have no problems and I certainly don't have to recalibrate after removing and reinstalling the glass. Everyone has a different process and setup. I've been very methodical with my machine because I do produce reasonably high precision parts. The fly fishing reel I designed I can print and have a completely functional reel (rotating spool and rotating handle) with no cleanup using a particular spool of PLA that I've dialed in for this. Switch PLA and the tolerances change enough that the spool needs to be reamed to rotate.

Also, I design keeping the layer height in mind and create parts that are an integral number of layers in Z.

Quite interesting observations. It sounds as if you've had the joy of working along the bleeding edge of technology!

I'm wondering if the possibility of warping was a thermally induced warp, if it was a perceived warp (when in fact perhaps some owners' issues were operator-induced), or if perhaps they simply weren't installed properly.

It could also be that the significantly higher thermal "volatility" of aluminum (than that of the glass) is inducing a bit more flexing.. did you ever play with stainless steel instead? SS (304) would be still far more thermally conductive (than the BS sheet), and (I'm assuming here) would be less likely to flex/warp, as it will deflect and transmit a thermal load far more slowly (and probably more evenly dispersed). IF in fact I could get stainless within tolerances, and adhere PEI to the surface, it seems to me that it could be adjusted to a reasonable amount of 'wiggle' for the average person's system.

It is an interesting reflection on this entire industry that it's so much in infancy, that many folks may be getting into something that's not "turn-key", and are prone to blame the manufacturer/supplier for their own issues.

Your expected tolerances are far more precise and closer than my own. I'm amazed you're holding those tolerances - I'd never expect to pull that off with my printer, primarily because I am using it for proof-of-concept and crude revision prototyping. I'm hoping the 3d laser SLA system (which should be here in 1-3 weeks) will be the ticket for absolute precision prototyping and parts mating.

It takes me a good hour of tweaking to get within reason on the printer as well - warm-up, equilibrating, measurement, adjust, re-measure, re-adjust, etc, etc.. annoying. but necessary. and i still get some pretty big sways..

It's made me consider a number of methods for an optical Z plane measuring device, which would somehow plug into the board.. Imagine the ability to take the unit to self-level the head for EVERY RELATIVE XY point, using say an optical sensor mounted on the side of the head! So then it wouldn't matter if your base plate was flat or level, or had ripples--the sensor would self-calibrate to the plate, and start from there.. Don't have an answer there yet.. but that's in the hopper for when in design my own 3d printer.


on another note-you mention an integral layer count. have you seen much variance in this? seems (to me) that the layers might in fact "collapse" a certain amount, as they extrude while in liquid form... what have you observed re: that issue?

Well, after a few solid weeks of printing on the PEI held down with silicone, the silicone has failed. I was printing with my bed at 100° for some persnickety ABS I have and after a few hours I noticed delamination bubbles. One of these was at he edge and confirmed that the silicone had let go. Bummer. I am going to try the 3M tape next.

Questions for those who use the tape...

It comes in 2.3mil and 5.2mil thicknesses, which did you use?

Also, I can get it in 1/2, 3/4, 1, 2, 3, 4, 6, and 12" width. I think the 6 or 12 is too wide and might be tricky to get down smoothly. 1, 2 or 3 seem about right. If you've tried this, what do you think?

http://www.amazon.com/gp/product/B007Y7 ... UTF8&psc=1

it didnt say a thickness, ive only printed up to 80deg, the ABS sticks fine with nothing applied to surface.

A quick google of the part # from amazon says it/s the 5.2 mil. Would you suggest something wider like 1 or 2 "? Amazon has those too.

this went on super easy, and with it being narrow, i think the air bubbles were pushed out easier without folding/creasing

Great, thanks. I think I'll try the 1" width. Might be a good compromise between not too many strips and easy to handle.

mhackney wrote:Well, after a few solid weeks of printing on the PEI held down with silicone, the silicone has failed. I was printing with my bed at 100° for some persnickety ABS I have and after a few hours I noticed delimitation bubbles. One of these was at he edge and confirmed that the silicone had let go. Bummer. I am going to try the 3M tape next.

Questions for those who use the tape...

It comes in 2.3mil and 5.2mil thicknesses, which did you use?

Also, I can get it in 1/2, 3/4, 1, 2, 3, 4, 6, and 12" width. I think the 6 or 12 is too wide and might be tricky to get down smoothly. 1, 2 or 3 seem about right. If you've tried this, what do you think?

Sorry you had that failure but happy that you reported it. The other option might be J-B Weld but I have not tried it.
I think the 1 or 2 inch max tape would serve your needs the best. This stuff is super sticky and if you get an air bubble under it or between it and the PEI, game over.
When applying the PEI to the tape, a piece of wax paper under the PEI should help as you can slowly slide the wax paper back as you go. One correction, if you get a
bubble under the tape while applying it, it could be punctured. I haven't tried the wax paper either, it is an assumption that the tape won't stick to it.

Thanks Eagle. I have some siliconized paper - the kind labels are stuck too. It might also work to as you described. That's a good idea. Tape arrives tomorrow.

I took my PEI off the glass so I can prep them for tape tomorrow. The silicone completely separated from the PEI and was adhered to the glass. A PIA to remove. I started with a single edge razor blade and made 3 passes. Then I washed the plate in Simple Green and used a Scotchbrite pad on it. I might have the cleanest borosilicate build plate in Massachusetts! But the deed is done and I'm ready for my 3M tape to arrive tomorrow. Meanwhile, I'm printing on blue tape at room temperature and getting a fantastic print. Of course, the bottom won't be "pretty" like with PEI.

I've got it on with the "TapeCase (468MP) - 12" x 12"

http://www.amazon.com/gp/product/B007Y7 ... UTF8&psc=1


couldn't be happier.


my parts are coming out near perfect.
I'm running bed temps about 30C *LOWER* than I did with Kapton tape.
I've not once had a surface adhesion (other than the first time when I forgot to reset my Z and tried to print in thin air).....

And no problems with air bubbles? How did you go about it?

cheers,
Michael

mhackney wrote:And no problems with air bubbles? How did you go about it?

cheers,
Michael

No issues with air.

1. I triple-washed the glass, after scraping it down with a razor blade. a cleaner, then windex, then isopropyl alcohol
2. I put the tape on, applying from one side across, with a 2' long 2" rod as a "flattening wheel", which I "steamrolled" the tape down.
3. I isopropyl'd the PEI, let it dry, then laid it down with a minimum of curling of the plastic. I was more worried about injecting some curl into the plastic than getting it down perfect.
4. weight.. 240 lb of batteries stacked on the plate overnight, on a flat surface. I figured that had the psi rate high enough to resolve most issues...

The biggest value I see is that I don't have to constantly clean, remove, reapply, and re-calibrate the printer..

I've been running small parts non-stop all day today - small interactive gears and levers for a product development. Usually had them printing back-to-back with less than 2 minutes between parts being finished, to starting the next set...

this would've never been possible last week...

I had one part which was a bit nuts... a somewhat hollow cylinder, 5.5mm diameter with a 1.5m hollow center, 22mm tall, with a 40 degree arm coming off it at 18mm high... printed standing on end.

No hair spray.
No tape.
No errors.

i'm sold.

PEI is great stuff. Did your material have a matte side and a glossy side? If so, which side did you put up? And what thickness of PEI did you end up with?

Thanks for the information. "Clean" is critical!

The stuff I got from Amazon was glossy on both sides. I decided it was leaving a little too smooth a finish, so I just used a brass brush to lightly scuff the surface of the PEI to be matte.

mhackney wrote:PEI is great stuff. Did your material have a matte side and a glossy side? If so, which side did you put up? And what thickness of PEI did you end up with?

Thanks for the information. "Clean" is critical!

Mine had matte/glossy..

I put the glossy side down, so i've got a matte surface to work from.

The really cool thing is that when I print now,if the print ends when I'm away (and this is common, as I'm running some 9 or 10hr print jobs right now), the product will pop loose after it's cooled just a bit.


A couple changes I'd recommend here.
1. I'm running a bed temp of 80C. That's actually WAY better than ever before (I was starting out at over 100C - which takes extra time and is a bunch of hassle)>
2. making sure you've re-calibrated the bed after you've placed your plate is absolutely critical.
- I can't over-emphasize this point. You *HAVE TO* dial the bed in, accurately. I've got mine "really close", but it's probably off by .01 or .02mm in one corner, and that's enough to notice an inconsistency when starting out the first 2 layers. It also means my "round" prints aren't actually round. Because a Delta-style printer triangulates everything, bed orientation & calibration IS EVERYTHING. Don't cut corners on that step.

I'm not sure what you mean by "making sure you've re-calibrated the bed after you've placed your plate" and "You *HAVE TO* dial the bed in, accurately".
I'm using PEI too with no problems so just curious if I am missing something.
Thanks

mhackney wrote:PEI is great stuff. Did your material have a matte side and a glossy side? If so, which side did you put up? And what thickness of PEI did you end up with?

Thanks for the information. "Clean" is critical!

Did you get yours mounted on the glass with the tape today?

Not yet. Have a few other projects. Hope to get to it tonight though. Will report back when done.

Holy1 wrote:I'm not sure what you mean by "making sure you've re-calibrated the bed after you've placed your plate" and "You *HAVE TO* dial the bed in, accurately".
I'm using PEI too with no problems so just curious if I am missing something.
Thanks

I'm probably using incorrect terminology here...

"recalibrating" - - - - making darn sure the head is 100% level to every angle of the bed... If it's not, you may have great adhesion on one side (or might even bang the head on one side), but have a gap elsewhere...

Making sure the deck is 100% perpendicular to the head plane across the entire deck is so very critical for accurate reproduction.

sorry if i'm using the wrong terminology here - perhaps Mike or somebody else can help??

An update. I had ordered 1/2" and 1" 3M tape. I started with the 1" hoping it would be less work. I don't know if I had a damaged roll or if this is a problem with the wider rolls but one entire side of my roll was stuck to the underlying layer. the end result was that the rubbery adhesive peeled off the backing and formed lumps as I attempted to apply it. It was very frustrating and I went through the entire roll hoping that deeper layers in the roll would be ok. They weren't. The 1/2" did not have this problem and went on rather easily. I left a little gap between strips and that should be fine.

Unfortunately, I did this at night and did not notice a hair had got trapped between the glass and the PEI so I've had to peel the PEI up and start from scratch. Of course, I needed to order some more tape...

mhackney wrote:An update. I had ordered 1/2" and 1" 3M tape. I started with the 1" hoping it would be less work. I don't know if I had a damaged roll or if this is a problem with the wider rolls but one entire side of my roll was stuck to the underlying layer. the end result was that the rubbery adhesive peeled off the backing and formed lumps as I attempted to apply it. It was very frustrating and I went through the entire roll hoping that deeper layers in the roll would be ok. They weren't. The 1/2" did not have this problem and went on rather easily. I left a little gap between strips and that should be fine.

Unfortunately, I did this at night and did not notice a hair had got trapped between the glass and the PEI so I've had to peel the PEI up and start from scratch. Of course, I needed to order some more tape...

Those loose hairs are from too much flexing.

It was my wife's!

mhackney wrote:It was my wife's!

Sure it was, we believe you.