Updated leveling process


#21

Absolutely perfect!!!


#22

Robob3ar, dude… look through the wiki and see if there is anything else that inspires you. This style is excellent and multi-language, which I love.

http://wiki.peopoly.net/doku.php?id=moai:start


#23

it came from deep frustration :slight_smile:
… actually never used to note stuff down, this one was bending my mind visualizing mirroring images…
… did this in 3dmax, as it’s easier for me than in illustrator :slight_smile:
… it was clearly just to the point - main information you use once you do 20 levelings… have to have deep insight into what I’m doing and taking notes - you think I’d do it if it worked on 1st try - but I’m glad I’m breaking into new habits, note taking… now, main thing, a way not to loose them when on paper

BTW anyone though about some pressure sensors which can indicate it’s same on 4 points - I was thinking it should be in the build plate - but then you got wires sticking out…
… oor, maybe - use some calipers stuck between bed and the vat … actually the pressure sensors could do that as well… so you set it to beep once you got it in some pressure range … gotta be quicker way


#24

I was just pitching an idea to Mark about that. Here is what I came up with. A little dipstick you clipped on the side of the build plate.


#25

I really like the style of the graphics though. It makes it easy because we don’t want to update the helper graphics… we can update the details, the text, easily enough. The graphics need to be easy to understand and general enough that we don’t need to update them. I put them on the wiki, and I’ll mess with the size of the other graphics to get them all looking better. I just want to get all the info there for now.

Do you want to do some graphics for the initial leveling procedure? Just so they all match on that same page, lol.

http://wiki.peopoly.net/doku.php?id=moai:leveling


#26

you don’t even have to go all the way down, hold it 10 cm above the vat, stick a 10 cm cylinder (or something) between vat and plate - hold the stick and screw them up in place until it fits
… making sure you have soft / wide cylinder edges not to damage the pdms - maybe make the bottom part of hard rubber - that might be the cheapest alternative

…also I’ll take a look, it’s way too much text for my liking actually :slight_smile: - will see if I’ll get the time, I mean graphics are actually speedmodelling with white color for light emmision, instant realtime render on default seettings

  • Mark what do you think

#27

ron… apparently I came up to same exact solution to yours for the level dipstick, just at like 10cm length…

  • can’t think of anything simpler

#28

Interesting idea. Is it meant to be used in conjunction with the leveling screws? It will clearly show that the build surface is too high, but not when too low. But maybe that is enough? Start too high then lower the bed to contact?

@Peopoly Mark, would it be possible to make the build surface Z-reset “live”, i.e., actually move the build plate up and down in real time using the control knob? Using these leveling tools, the user could manually raise-or-lower the bed until it just made contact on one corner and then adjust the rest to match using the platform screws. It would probably require a separate calibrate function linked to Z-reset, with a firmware set limit to prevent a user from over driving the build plate into the vat.

It wouldn’t be a huge change, but I would not have to use Lyndondr’s feeler-washer method anymore.


#29

Yes, I would imagine that you clip 4 of them on each corner of the build plate. Then keep tightening until you see the red show up in the window in all corners. It would really only replace the 'tighten the nut until a piece of paper cannot fit inside".

I think after you did that you would be required to print the 4 cylinders and get a more accurate measurement. Then regarding the cylinders, need to work that out so its an even number … so 10mm exactly would be desired as an example.


#30

I agree, the feeler gauge levels would only be for rough adjustment. If one could adjust the z-reset live, then both the mechanical and firmware rough leveling could be done simultaneously.

IMHO, the test columns could really be any size, as long as that size is defined. IIRC, the major concern with the size was getting enough of the column out of the ‘compression zone’ defined by the base layers.

The goal would be to get 4 columns of the same height. Z-axis print scale calibration could be done later with the 30mm (?) columns.


#31

Well I’m glad to know someone tried it.

When I did the advanced leveling my concern was how even the test pads printed in the first millimeter. At the time if I had a print failure it happened in the first 5-10 layers. Anything beyond that you are pretty much home free.


#32

I tried the washer method as well. The washer inside diameter was just a little too big, so it sat on the groove of the nut and wasn’t completely flush with the plate. Then I tried wingnuts and they didn’t feel tense enough… I went back to the paper method but then immediately did the 4 cylinders.

There must be some mechanical solution to this and I bet it’s obvious, because this isn’t breakthrough science. Mechanical engineering is one of the largest fields in terms of historical record. I imagine the build plate moving into place and locking. Then I imagine releasing a valve and the vat slowly moves up, like a piston, until it stops. There is still room left in the springs so it is pressing and hence the bolts protruding out, but its at its contact point on all 4 corners. Then you can just lock down the bolts. Similar to shock absorbers.

Ok, now I’m thinking of an old printing press. It has a Z-axis plate that moves down and presses the ink plate into the material to be printed.

The real problem is measuring the amount of bolt or slack leftover from the springs pressing the vat on the build plate. What if they weren’t bolts at all, and they were just rods that then had a quick release tension locking mechanism.You could then just slide the locking mechanism up the rod and lock it in place with the tension lever.

Ok, instead of reworking what about a cheap torque screwdriver? lol Set it to 10lbs or whatever and do it.


#33

The issues are precision, complexity, and price: the mechanism has to be precise enough to match the necessary tolerances, but not be unwieldy or cost more than the machine itself. Personally, I think the current mechanism meets that balance, the question is one of measurement. One thought I had was exploring an optical solution: if the PDMS deforms under pressure, then that might be observable with polarized glasses, which could assist the leveling process.

The other option, which may make more sense, is not focusing on the vat platform, but rather on the build surface. A manual or self-leveling build surface would be easier to observe and obviate the need to open the machine after initial setup. Also, there is more space for flexibility with the build surface than with the platform. And, the build surface is meant to be replaceable, but the platform not-so-much.


#34

The washers I had on hand had a 4mm hole so they were just large enough to fit over the studs.


#35

It would have to be strong enough so that it doesn’t move with the peel forces required when the build plate is closest to the vat.


#36

Absolutely, which means a positive lock off that is mechanically redundant, e.g. positively adjusted in both directions. It would probably require a jackscrew mechanism at all 4 corners, each with locknuts on both sides of the threaded follower. Safely clevis links have something like this, IIRC. It is doable, and probably wouldn’t require a huge amount of re-engineering. Also, the actual range of motion does not need to be big, I am guessing that you need only about 1-5 mm of total movement range in the build plate.


#37

Hi all, just joined in because I’m leveling mine.
why not use Piezo sensors? They are cheap ( a few dollars for 4), accurate and you can drill a hole in them too. Put them going to a raspberry pi or other board and spit out a grid.


#38

There are spare pins on the board, we could mount 4 piezo’s with a hole and washers and edit the firmware to show those locations on the screen. Translate the pressure into distance or turns and you can set it live while on the screen then run it again to verify. That way you don’t have to guess.

It took me 7 tries with the towers (which works well by the way, Thanks!) to get it within 10.8 to 10.87 :joy:

Each time I set it I pushed the bed up and down to try and let the springs find their spot a bit.

Next is cal cubes but it’ll have to wait till tomorrow.


#39

That is an interesting idea. Do you have any application examples you can link to? Maybe just an Arduino add on.

I have an idea for being able to adjust the level from the top but at this point it’s just an idea until I can dig into some proof of concept. I’m working on @peopoly for some of the design files/models so I don’t have to reverse engineer everything.


#40

Something like this is already pretty much built:

Probably keep it simple and let a LED light come on to tell you to stop with whatever pressure you set.

Just thinking out loud because it shouldn’t of taken me that long to level it and if you switch vats for running multiple colors I’m thinking you have to level it again?

I was thinking about throwing a PI in it for a camera looking up at the build, so it wouldn’t be a big deal to add simple sensors. I’m not sure if you can see a failure happening on camera with dark colors though, maybe you can see that the layer is not lifting off the pdms? Just my first day with it :grin: