gr5

Well cor3ys I've learned a bit since you posted this picture: Namely I have one of my own. That picture shows the problem nicely. The belt needs to be lined up with the rod. So after you push the rod back in, loosen the set screw on that upper pulley in the picture. Then slide the pulley so it is perfectly centered above the rod in the picture (the lower rod). Then retighten the heck out of the pulley. When it is centered, the black spacer should be now touching the case and doing it's job. Now of course the *other* side will be loose so you need to fix that side also. edit: actually the other side is probably fine.

Yay! Next print 3! Just kidding. Well if you find you need to improve quaility more: 1) .2mm layers often comes out better than .1mm layers. It's counter-intuitive. But if there is any error in Z it shows up worse with .1mm layer because some layers are over extruded followed by an underextruded layer. If your Z has no stickiness or slipping and the z nut doesn't move and everything is perfect then .1mm might look better. 2) slow it down even more if you want high quality. For a small part I would lower from your 70mm/sec to 20mm/sec. It's so small it won't take that long. Be patient. I learned that from watching the UM people at the MakerFaire NYC. They have banks of dozens of printers in a room so they don't care if it takes 20 hours for a print! 3) If you are going that slow, consider maybe also going even cooler to 190C or even 180C only just to lower the stringing issue. Printing 2 parts means lots of stringing and that can be elimintated at 190C usually. Or if the second part is nice and big like a 10mm cube with 20% infill.

I think you need to take a better picture of the first item. And put an arrow to the spot that you don't like. I don't see any under-extrusion - it's just a little blurry on the "worst spot". Under-extrusion can be caused by many things and a "tangle" is quite common - especially if the filament is falling off the reel. Especially on a new reel. Or if you don't push the reel against the back of the UM. But... there are 10 other causes for under-extrusion. One being dust and your objects look very dusty. But I'm not convinced you have any under-extrusion - so please zoom in or clip the photograph closer in to just the bad area and make sure it's clear. Part's of your photographs are amazing - I can see each .1mm layer like rice farms in China. Like steps in a stair case - so perfectly flat. And I can see a weird oscillation. Maybe caused from the original STL file.

Resin printers like Formlabs only print ONE material. I know little about that material. I don't know if it can handle temperatures found in a hot car on a sunny day. ABS can. Normal PLA can't. I don't know if you can change the color. I don't know if you can get multilple colors. But the UM can print dozens of material types and lots of colors. The UM can print nylon, PLA and ABS all easily. And there are many varieties of PLA including PLA45, PLA90, PLA with wood or stone powder mixed in, PLA with carbon fibers mixed in. But right now the B9Creator only prints in red or another shade of red. Those are the only 2 colors and they are both red. That is typically the biggest reason for not getting a resin printer - the material you get out of it. On the plus side they are AMAZINGLY precise and small and accurate. On the negative side they have all the same issues as a FDM printer regarding support, overhangs. e.g. you can't print someone's face easily on either printer because the chin and nose hang over "thin air". There are tricks! But it's a challenge.

I have never printed with ABS but I read a lot. Most people heat the bed up. very hot. And they create "ABS glue" by mixing some spare ABS with acetone and letting it dissolve for a few hours. Then paint the "glue" onto the glass bed. Let it "dry" and then print on that. Should stick like you wouldn't believe. You may have trouble getting it off the glass although if you let the glass cool completely, the difference in thermal expansion of the 2 materials will help quite a bit. You can also paint on blue tape but it will destroy your tape getting the part off. You will need razor blades. You can then soak the bottom of your part in acetone for a few minutes and the tape should slide off. Most people don't seem to use raft anymore. But I can see how it is nice as it flexes as the part shrinks and still hangs tight.

I don't know much about raft at this point, but in advanced settings there is a "gap" you can set in the support material section ("Distancy X/Y (mm)". Set that to zero and compare in Cura "slice view" to see if that helps.

Your post gives me all kinds of ideas. It's common to have under-extrusion during acceleration (start of a string) and over extrusion at the end. This is caused by the delay between when you ask for more filament and when it comes out (delay mostly caused by bowden tube and other stretchy/springy physical elements). This "error" is reduced if you print at slower speeds but should also be reduced if you greatly lower acceleration parameters. So I'm thinking that simply lowering the speed when you get near a bridge would help. Also lowering the XY acceleration for the section of print that involves a bridge might help. You want to lower it a LOT. I would lower it to about 1/10 of the current value for a test. I have many experiments on my list right now so I might never get to this one, but this is very intriguing!

Wow. First of all, your photos don't show #2. Did you do many more tests? Can you upload more pictures to the same album - put notes with each picture that describes what it is showing (if you have these pictures already). Oh! Daid please! Please add comments to show each individual bridge line! That way this guy can write a plugin to do some experiments to improve bridging string strength!

Great post - I rarely edit a post but I did yours - hope you don't mind. Let me know if you want me to revert to original. I did some bridging tests also recently but your zoom-in-photo is fascinating! It makes me think Cura should output a little extra flow for the first 2 millimeters maybe? Currently post #17 (but that will likely change within a month): http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/?p=25304

That is very good photography! I zoomed way in and could see quite good detail! 1) I'm pretty sure those lighter layers is white PLA. It's strange but sometimes when you change colors, the other color can stay in the print head for an hour before coming out. If you use higher temperature (240C-250C ) for a few minutes while changing filaments and pushing as much filament through as possible you might be able to get the other color out sooner. 2) How did you get the white ring inside the pink part? Was that printed separately and then assembled later? 3) How many line segments do you have for each circle? Wow. Very nice. I had a similar issue to you where I printed an orange part (pumpkin) and then later printed these 3 white people and at their waist (half way up) some of the orange PLA came loose and changed the color: Too zoom in, you need to do 3 things: First click the image, then right click it and choose "view image" then click it again. This is what I had to do to see your image full size.

a quick test? lol! There are known problems with Marlin reading the SD card on UM2. What version of firmware do you have (go to the advanced menus and it's in there under "version"). I think I have 13.10-5 but I"m not sure if that is the version with the fix or not. I'm relying on memory of Daid's posts without looking for it.

Whatever works!

The shipping to the US part was pretty fast. 3 days. Actual days. DHL doesn't seem to stop on Saturday or Sunday. It kept moving along as I could see on the tracker. It shipped at 3pm Netherlands time on Friday and arrived 3pm Boston time on Monday.

Yes I want to try PVA/wood glue and I want to try hair spray but most important was to try the glue stick that comes with the UM2 to help future UM2 users (and me). Glue stick cleans up very easy with water: wet sponge or wet rag. You also don't have to wait for glue stick to dry as far as I can tell. And glue stick is very fast to apply (don't need to unscrew a jar lid).

I keep notes on EVERY print. I have a notebook that sits in the bottom of the printer. In cura speed was 50mm/sec and I ran at 50% so: 25mm/sec and temp 195C. I was printing 3 people at once so I don't think I hit the "minimum layer time" but I'm not sure on that as it isn't calculated perfectly. When the printing got to the hips I noted excessive stringing which was surprising. So I lowered the temp for the upper half to 190C and slowed down to 40% (20mm/sec). It still only took probably 10 minutes to print. Not sure (don't usually write that down). Normally at 20mm/sec and 190C I get zero stringing with this particular PLA but I got lots of very thin strings. I think it has to do with the fact that it doesn't get much time to cool down. Fan was at 100%.

So... Now that I've seen Ian's photos and looked my UM2 over carefully - there is a system of locked pulleys, black spacers and pulleys against the walls of the inside of the UM2. 8 of them. NONE of the rods should be sliding around. If they are then either you are missing a black spacer, or more likely one of your set screws in one of your pulleys is loose. The one with the problem will actually always be the one closest to where the rod is poking *out*. So push the rod back in and slide the pulley against the spacer (if there is one) and then against the outer wall, and then tighten the pulley set screw.

I did a big experiment today using the UM2 and printing on glass. I learned a lot. I tried at room temp (21C) through 75C. I only researched how well parts stick to the bed. I did *not* research how temp affects warping/shrinking issues. I only printed PLA on glass with and without gluestick. I would print the bottom of the UM Robot (first 4 layers) and then remove it with a screwdriver pushing horizontally. I pushed the screwdriver with a scale that goes up to 30 pounds which was barely enough for one of the prints. Here are my conclusions: You can print on freshly cleaned glass no problem - you need the filament to stay hot long enough to fill in the gaps and make a good surface if you want it to stick. So for example 220C nozzle, 30C bed was not enough - 1/2 pound force was enough to remove. Wimpy. Yet 30C/240C nozzle took 14 pounds force. At 220C printing, the bed needs to be at least 45C to stick well (14 pounds). If you lower to 40C it only took 5 pounds force to remove. If you add gluestick you don't need any heat (but it helps a little). I printed at bed temp 21C (room temp) nozzle at 210C with glue stick and it took 19 pounds force to push the robot bottom off. With 45C bed, 220C nozzle, and gluestick it took 30 pounds force! Thats enough to put holes in the base of the robot print. The other thing I discovered is bed temps at 60C and higher were bad. The part was still soft and it didn't take much force to remove it and when you did it wrecked the part. 220C/60C no gluestick took 11 pounds but it destroyed the part. 220C/75C took only 1 pound of force and it folded the robot base almost in half as I pushed. Also if you use gluestick the amazing thing is you can soak in warm water for just a few seconds and pry it off slowly and the water disolves the gluestick nicely and the part comes off with only 1 pound of force even if otherwise would take 20-30 pounds. edit: I also printed on plain fresh blue tape and it took over 30 pounds force. I couldn't push hard enough and had to turn the screw driver sideways to pry it off (then it came off with 30 pounds force). With alcohol it sticks much more - probably over 100 pounds force but I would probably damage my bed. So here are my recommendations. For medium/reasonable stickiness print at 45C-50C bed temp and use no glue stick. If you want it to stick like crazy use 45C with gluestick but beware it is hard to get off without soaking in water. All of this ignores warping issues! I want to do warping/overhang tests at some point but I'm not yet sure how I will test this in an easy, repeatable, objective manner. Here are some of the results in photo form, lol: I cleaned the glass with windex and a rag before every print! Here's all the raw data: bedtemp/nozzle temp pounds to remove, notes 220C/50C 11 220C/65C 5 220C/75C 1 (part just kind of folded up - much too soft - see photo) 220C/50C .1 220C/50C 1 Above tests were with putty knife that sometimes slipped under part too easily so I kind of threw that data out. Remaining were with screwdriver and blade vertical 220C/50C 10 220C/40C 5 220C/60C 11 (but part was wrecked - see photo - part with notch) 220C/50C 14 220C/30C 0.5 (part had warping/lifting on corner before I started to remove) 240C/30C 14 (hotter filament helped a lot!) remaining are with gluestick 220C/45C 30 (bottom right in photo - part has 2 notches - first notch was only 20 pounds force) 240C/21C 16 210C/21C 19 (even at room temp - wow) 220C/45C 20 (mostly repeatable, yay!) 220C/45C 1 (soaked glass plate in water in sink for a few seconds while pushing/lifting lightly with fingernail)

You need to level to within about 25% of the first layer height. In cura you can set the first layer height thicker but if the first layer is .06mm you need the bed accurate to about .02mm. This is one fifth the width of a piece of paper. Also when the print head warms up it expands so you have to level with a hot print head, then after you get it perfect with paper, you have to twist the 3 knobs a little more to get it a little closer. How much to twist? I don't know yet. I guess one can figure it out with 2 pieces of paper to see how much to rotate those thumb screws to achieve one width of paper in height change. Your photo looks EXACTLY like what I would expect. In some places you are too close to the bed and the pressure builds and builds until suddenly it can't take it and you get lots of extra filament squirting out the side of the nozzle which causes blobs, or thicker areas. What I do with the UM Original is print an extra large skirt and twist the Z axis by hand (difficult to do on the UM2) fighting the stepper. This does not dammage the stepper motor. By the time it does the final skirt pass either I have levelling perfect or it's time to abort and start over.

Just to explain further - after it finishes one layer of the main part, it goes to the second part to print a layer there and gives the first part time to cool down.

You linked to a "dial indicator" and your link simultaneously links to the spring portion - some spiral part. I don't see any cylinders. But the biggest problems are usually cooling related. You might need to combine two tricks. The first trick is to lower the temp to 190C and make sure fan is on at 100% min and max and set layer time to at least 5 seconds. The second trick is to print 2 at the same time - set the gantry height in your machine configuration and print two. It sounds silly and wasteful but it makes a huge improvement for very small objects such as these people I printed recently:

That sounds crazy. You cancelled a print because it *might* fail? I removed one of the endcaps of my old UM Original and the rod sticks out but if I just ignore it, it never gets worse. It's in a happy place now. Some day I will look into it and see if I can adjust the pulleys (slide them along the rod and re-tighten) but for now it can print for months and months like this.

One more post and you can do anything! So just reply to this and say "replied" so I can approve it. On gallery page there is a blue button on far right that should say "upload". You can alternatively post a pic on the web - for example imgur. Then click the "image" icon where you are posting and then insert the URL when prompted. If you use the gallery, after you upload, start a new post and click on "my media" next to the smiley face to insert your picture into your post.

Oh - now that I think about it I'm not sure if you can use kisslicer with UM2. I really don't know much about UM2 yet. I'm more a UM Original expert. The "joris" setting is now called "spiralize" in Cura 13.11.

By the way these "outer dimension" errors are caused 90% due to how much PLA shrinks as it cools. Very little of the error comes from errors in the printer. Different PLA shrinks different amounts. PLA45 (from germany) shrinks much less and is much easier to print because of this and your cad model needs less adjusting. But it costs much more and only comes in one or two colors (black and white I think).

When one firsts prints something simple like a cube, cylinder or cube with a round hole, the tolerance is annoyingly off. Converting to mm, a 20mm by 5mm part will probably print out to about 19.5mm by 4.6mm. However this is easily fixed by increasing the part dimensions by .5 and .4mm respectively. After doing that you can easily get tolerances (repeatable tolerances) to about .1mm error. The z distances are usually spot on because the lower portion of the part is cool while it is printing the last few layers. Inner holes in the part (like a shaft or a cylindrical hole) are much worse. For many reasons they come out quite a bit smaller than expected and a 3mm hole will come out probably 2.4mm. If you change filament, change printing speed, tighten your belts, change printing temperature then you might have to readjust your settings by another .1mm if you need that kind of accuracy. If you will be printing lots of small parts (under an inch long) and you don't need to print quickly you can switch your nozzle to a .35 or .25mm nozzle and get finer detail. Your corners of your cubes will have tighter radius. You can't switch nozzles on the UM2. But on the UM1 you can get lots of other nozzle sizes for well under $5 per nozzle including shipping.