TO shim or NOT TO shim

[Nylocke]

I'm building one from scratch, the only thing I'm running into is lack of money (that's what I get for being in high school) if you want help sourcing the parts for your own, I can show you where I got mine. I found all of the bearings and bushings needed, and you could buy the belts somewhere else if you're really hardcore, but I'm just getting those from ultimaker. I'm also planning on buying their electronics, though I have my RAMPS from my Rostock Mini sitting around because I'm in the process of rebuilding/buying a new hotend. But if any of you want to build an ultimaker from scratch, I'd love to help source the parts.

[Eaglezsoar]

I'm building one from scratch, the only thing I'm running into is lack of money (that's what I get for being in high school) if you want help sourcing the parts for your own, I can show you where I got mine. I found all of the bearings and bushings needed, and you could buy the belts somewhere else if you're really hardcore, but I'm just getting those from ultimaker. I'm also planning on buying their electronics, though I have my RAMPS from my Rostock Mini sitting around because I'm in the process of rebuilding/buying a new hotend. But if any of you want to build an ultimaker from scratch, I'd love to help source the parts.

Mike, if you would do that I would certainly appreciate it. I have Ramps and a Rumba card and motors. Please realize that there is no rush. My email is [email protected] if you would use that for communicating with me instead of cluttering up
the forum I would appreciate it. I don't think SeeMeCNC would like us sending too much communication about a competitor's product. So you are still in High School. Enjoy your young years for they will pass faster than you know. I am 61 years
young.

[Nylocke]

years young, yes. I'll send you links after robotics tonight. sorry Steve, but we are talking about the Ultimaker :O

[MSURunner]

I got them back when they were only available as kits (after two of these, I'm beginning to think I ought to wait a bit longer). The kit I purchased was back when the LCD was optional (got it, AWESOME and much of the Marlin code to support LCD appears to have been written by UM given the comments), did not have a spring adjustable extruder, and the hotend did not utilize a teflon barrier piece. After a clog in the hotend once that cause the thermocouple connector to disconnect and a runaway ensued, causing the PEEK to burn (which isn't easy). So I upgraded to the current hotend design and it works great. I also sweet talked Daid (the guy that wrote the code for Cura) into getting me the laser files for the new extruder design. So basically I what amounts to the current UM Original, with some tweaks. It is an impressive machine. The boys in Engineering program at one of the other schools in town have $30K+ Dimension printers that I can produce similar or better results than on most prints. The new UM2 looks great, but if you are an experienced user of 3D printing, the general consensus is that the UM Original is just as proficient of a machine. The build is very straight forward as well, so I wouldn't hesitate to go with a kit at all.

DF Robot has many of the parts that, in appearance at least, are clones to UM parts. I have heard of several people using them and being successful. Alas, as stated, we probably ought not clog up a forum with a competitors bot Email sent

[bvandiepenbos]

I use pan head screws with washers on my Onyx instead of the OEM flat head ones. I did not countersink the Onyx mounting holes either. I just lightly snug the screws down. That way the Onyx can move as is heats and expands without buckling. I have never had issues with bed warping. Stays pretty darn flat. Oh, I also use a thicker piece of glass (1/4" plain glass) maybe that stays flatter than the thinner SeeMe glass plate?

[0110-m-p]

I use pan head screws with washers on my Onyx instead of the OEM flat head ones. I did not countersink the Onyx mounting holes either. I just lightly snug the screws down. That way the Onyx can move as is heats and expands without buckling. I have never had issues with bed warping. Stays pretty darn flat. Oh, I also use a thicker piece of glass (1/4" plain glass) maybe that stays flatter than the thinner SeeMe glass plate?

I'm assuming that to do this, you have a piece of glass with a diameter that is small enough to fit inside the pan head screw bolt pattern then?

[bvandiepenbos]

I use a square piece of glass that just fits inside the screw heads.

[bubbasnow]

update

[img]https://lh6.googleusercontent.com/--GhS ... 214605.jpg[/img]

so i cut the snowflake, it seems like it did improve quality inside the inner circle. the top circled areas are still low, the .2 layer heights do not bond to the glass. the bottom circle looks like its too high and the nozzle is blocked for a inch or two.

[lordbinky]

What I did when I was trying to fine tune my settings was make a square in openscad, well I made 3 (10,50,150mm), that were just one layer thick (I was getting it down to .02 mm layers). The patterns that come out from those 1 layer prints were very useful for getting everything tuned just right. The patterns and changes in that one layer hold alot of information about your printer's calibration. I was going to write it up in detail but the universe has decided I don't need any 'spare' time recently so I thought I'd post at least the concept right now.

[bubbasnow]

Looking at the OP and my last picture, the right side of the bed (while it has improved) remained the same.. but the left side has changed totally. is their an exact torque that i should be applying to these screws?

[lordbinky]

I have been going off of my single layer prints for awhile. I had to say F'it to the dial indicator since I would screw things up somehow swapping it out with the hotend, so I just based my adjustments off of my actual print results. I was printing lithopanes so results mattered more than what something 'should' be. *shrug*

You get a better picture of whats going on when you print a single layer square (I guess you COULD do a circle but the square lets me see results in the cartesian view). So based on the picture you would want to raise the positions at the base of the X and Y towers (lower the set screw) for and that would clear up two of your problem areas.

I picture it this way. The center is your pivot point for your adjustments, it essentially stays the same. If the printer is a little low at the base of the X tower, then you will be inversely high directly opposite that tower. This is the point between the Z and Y towers that is circled.

You have two primary reasons for the point at the base of the X tower (I'll call this X_t for short) and the point equally distant from the center and opposite of the X tower (I'll call this -X_t). The first reason is the X tower is not perfectly square. The other reason is your endstop calibration. If you make the endstop screw adjustment you should be able to get the points X_t and -X_t to be the exactly same whether they are both high or low compaired to the center is a printer radius adjustment, but that can be easily fine tuned once you get this straightened out.

The hard part about fine tuning the printer is that we simplify what's going on for a reasonable mental model that gives you less headaches. Also, reducing the confusion that comes with trying to communicate what's going on to another person is another damn good reason. The trade off is it can make some results just not make sense, then we skip some of the causes of issues because of our simplied mental model and things don't get better. One of the things we simply is the assumption of is that the printer's movement is a plane, which is only a hair short of true if your printer/delta radius is spot on to the last decimal point and your towers are absolutely square. Otherwise in some way the actual 'plane surface' output of the printer IS a bowl of some sort. Using that mental model makes a lot more sense and easier to identify what is slightly off, although it lies on the path to madness if anything is more than slightly off.

I believe an auto-radius could be coded with a 7 point calibration (center point, the points at the base of each tower, and points equal and opposite the towers to the center point), but that still has dependencies on certain things being absolutely correct on the printer. My mind is shying away from further thought into that right now so I'll stop here

[cope413]

You can go back and read some of kbob's posts on calibration, but there's a problem with machines like the max (and kits in general) - we don't have the exact measurements for things like carriage offset and effector offset. After reading kbobs experience, I tried to measure mine and found the same variance in my numbers from SeeMe's defaults in the firmware. If we had all the variables within +/- .02mm or so, it would be MUCH, MUCH easier to get the radius properly calibrated.

As it is now, it's pretty much a crapshoot - lots and lots of trial and error - to get the Max to print out to 280mm diameter. Depending on your tolerances, it may not even be possible without getting more accurate measurements.

I have no idea how that could be done with a z-probe because it doesn't seem like it's possible to measure those values with a probe. If those values aren't correct, it will dome. The machine has no way of knowing it's doming or not, so it seems like the only way to fix that would to literally be to probe every single point on the bed.

[bubbasnow]

it seems like the issue is the screws holding the expanding bed in place. what if i take out the screws from the onyx, and only screw down the snowflake, and just use clamps to hold down the heat bed?

[Batteau62]

I've been thinking of trying that also. I put 1/2" metal stand-offs under my snowflake when I built my max, so I have the room for clamping. I'll post if I do it. Interested if you try it too?

[bubbasnow]

[img]http://www.harborfreight.com/media/cata ... _17346.jpg[/img]
$1 from HF
http://www.harborfreight.com/1-inch-cap ... 39569.html

[dpmacri]

it seems like the issue is the screws holding the expanding bed in place. what if i take out the screws from the onyx, and only screw down the snowflake, and just use clamps to hold down the heat bed?

What size screws did you use? I can't tell from the pictures how big the heads on yours are, but the heads of mine (they're #4-40 per the instructions) easily fit in the holes:

#4-40 screw to hold down Onyx heated bed

[bubbasnow]

my screws are the same as yours, they fit below the surface in the countersunk holes. I'm just having uneven prints towards the edge if you look at the other posts in this thread. it seems that im getting minor warping maybe caused by the bed being locked down. some people have this issue and some don't.

[bubbasnow]

[img]https://lh6.googleusercontent.com/-rRnr ... 021159.jpg[/img]

So, today i took the beast apart and measured everything twice before i put it back together.

I calibrated the end stops and center points.. all is well

I screwed the snowflake down, and tried a floating heatbed by using clamps around the edge. it seems i have having the same issues with .2 layer heights

Will the auto level functions fix this issue?

This is kind of aggravating!!

[edward]

It depends on the source of the errors. If it is just variations in the build plate, then Johann's G29 should fix it.

Apparently a new update of Repetier's development branch has a rewritten auto-radius that Roland claims is working, as indicated by 626Pilot here: http://forum.seemecnc.com/viewtopic.php ... =10#p21737 From the commit log it looks like it was added on Nov 10.

So.....maybe? I wouldn't hold my breath.

If you do try and have any results, good or bad, let me know so I can update the Auto-Calibration sticky: http://forum.seemecnc.com/viewtopic.php?f=54&t=2765

[bubbasnow]

It depends on the source of the errors. If it is just variations in the build plate, then Johann's G29 should fix it.

Apparently a new update of Repetier's development branch has a rewritten auto-radius that Roland claims is working, as indicated by 626Pilot here: http://forum.seemecnc.com/viewtopic.php ... =10#p21737 From the commit log it looks like it was added on Nov 10.

So.....maybe? I wouldn't hold my breath.

If you do try and have any results, good or bad, let me know so I can update the Auto-Calibration sticky: http://forum.seemecnc.com/viewtopic.php?f=54&t=2765

i would love to be a test dummy, but i would need some serious hand holding if i have to dig into the repetier and start changing things.

If i would just have to purchase a switch and print a rod/assembly I am game!

[edward]

You shouldn't need to change anything other than possibly some new Configuration.h parameters. These are things like the X,Y,Z offsets for the probe and possibly what pin it is connected to. There might be a couple of others, but if you were able to configure your machine to this point, it shouldn't be too hard.

If i would just have to purchase a switch and print a rod/assembly I am game!

This is really all you need. You can use something as simple as a micro-switch and some kind of clamp, or you can use an automatically-deployable non-contact Hall-effect probe. If you're just interested in testing the algorithms, all you need is a sensing device with decent repeatability, for which the end-stop micro-switches seem to be quite good.

[Eaglezsoar]

You shouldn't need to change anything other than possibly some new Configuration.h parameters. These are things like the X,Y,Z offsets for the probe and possibly what pin it is connected to. There might be a couple of others, but if you were able to configure your machine to this point, it shouldn't be too hard.

If i would just have to purchase a switch and print a rod/assembly I am game!

This is really all you need. You can use something as simple as a micro-switch and some kind of clamp, or you can use an automatically-deployable non-contact Hall-effect probe. If you're just interested in testing the algorithms, all you need is a sensing device with decent repeatability, for which the end-stop micro-switches seem to be quite good.

Edward, would the one seemecnc created work?

[edward]

Are you talking about the yet-to-be-released EZ Probe: http://forum.seemecnc.com/viewtopic.php ... it=EZProbe ?

I don't see why not. Again, all you need is a switching device at a known location relative to the tip of the nozzle to constitute a Z-probe.

[Eaglezsoar]

Are you talking about the yet-to-be-released EZ Probe: http://forum.seemecnc.com/viewtopic.php ... it=EZProbe ?

I don't see why not. Again, all you need is a switching device at a known location relative to the tip of the nozzle to constitute a Z-probe.

Yes, that is the one.

[bubbasnow]

so i took the glass off, loosened all the screws, heated the bed up to 100c, took my plastic level and pressed in the center of the heatbed tightening the screws at both ends in a star pattern. checked all the end stops and center again.. now i have a even printer surface....maybe until it cools, idk.