Yoter

Ruling out the limit switches, I went to swap the motors as I was guessing that was my next step one. Is this amount of discoloring normal? I didn't notice it being this bad when I was in replacing the hotend heater a few months ago. I was wondering if adding active cooling to the next board may help. The problem was random so I didn't think I was looking at heat buildup, but now am re-thinking.

Well, I guess I ruled out a slicer issue. This was sliced with Cura. I may try a fan under the machine to see if it is a heat issue after all. It did seem to slip back Y+ later in the print, about 1/2# or so for the last six to eight layers.

Its amazing what will kill us once you set up agencies whose job it is to tell us what will kill us! It's almost like they have to find more things to justify their existence!

Honestly, nothing related to the Ultimaker made me suspect end-stops, but I have a plasma table that if the end stop is tripped mid-process, it will quit feeding voltage to the motor but keep running code so it does almost this exact thing, continuing to run once the end-stop is released while skipping movements directed while it was interrupted. I did just trip an endstop on one of my other printers and you're absolutely right, it ignores the input. I guess I got frustrated and forgot I have a known-good printer sitting next to it to test my ideas on. I'll throw the ones I ordered in my parts cabinet, or use them on another project. I guess its back to square one... Now I'm not too sure what square one is. I'll see how it handles the Cura-sliced model it's running today, then move my questions over to the Simplify forum if it takes care of the issue. Edit: To answer Tinkergnome's question, I do print via SD card. My other printer finally freed up and I am running a couple models that have failed on it, that should show for sure if it is a slicer problem. Just had to wait on a 60 some hour print to finish.

Just saw this and wanted to weigh in. I donate printers to schools and support them and assist classes with projects. I have printers in three schools and have seen three different ways that they have been implemented, and these are my observations. 1. You have to have one staff member or a small group of staff who "owns" it. These teachers typically take a day or series of evenings working with me on the printers and learn how to set up, maintain, and troubleshoot them. 2. After school programs are going to see the most beneficial use of the printers. Every kid there is interested in the technology and process. It is too easy for 3D printing to simply become a filler activity in the classroom. 3. The kids are going to learn the CAD faster than the teachers. They were raised in a strictly digital age whereas the teachers as a rule are not. My own kids taught themselves Tinkercad with the tutorials and YouTube videos which is what set me down the path of getting printers to schools. It was amazing to see what they came up with after a few hours of playing with the program. 4. Schools need help. As we've seen in other replies, 3D printing is slow and it takes a long time for a class to go through a cycle of printing an item for everybody. If one of the classes at one of the schools I have printers in is doing a project and reaches out to me, I offer to take a pile of files and throw all my printers at it over a weekend. I have two or three buddies who do the same. As long as the prints are not huge, we can do an entire grade's project at a middle school over a weekend. We do still encourage printing at the school, but without access to more printers, the kids would never have gotten to take home their own designs. Finally 5. Teachers need help finding projects that add to their lesson plan. It is easy for them to see that the printer is engaging and interests kids, but converting that into a meaningful addition to a math course, or history course is much harder. High schools seem to have an easier time as they have more specialized courses, but elementary schools and middle schools have a tougher time of it. I know this isn't all pertinent to your original questions and I am not the demographic you are looking for, but I've gotten to be part of bringing 3D printing to three schools I provided printers with as well as some other local schools that got printers independently and were referred to me for help with setting them up and integrating them. Overall, the results are scattered. Point one about one or a few staff members "owning" it and getting engaged with it seems to be the determining factor. Of the three printers I donated, the two where I talked to a specific staff member who was interested and thought it would be beneficial are busy all the time and the third collects dust then prints UM robots on back to school night.

Hopefully that uploaded the images! The shift is very abrupt. I set the print back on the bed to show the direction it always seems to take. I did try to stop the head while it was traveling this morning. I moved it to the far corner and tried to hold it when I directed the machine to home. It did instantly start skipping steps and I didn't see any slippage in the belts/pulleys. Also, once it homes and the servos are powered, I don't feel any backlash. I'll try a slice in Cura to rule out a Slicer issue. I've never had an issue like that with Simplify, but there is a first time for everything! While I am waiting for the print, I do believe I am just going to order the stop switches. They're cheap enough I'm willing to swallow my pride as a technician and just throw a pair at it and see what happens.

The biggest hurdle is going to be the physical properties of the material as it is laid down. Even if you start with a food-safe thermoplastic, there is no way a material manufacturer could get it certified universally in 3D printed form, as every printer prints different with different materials in its filament path, and two identical 3D printers could be printing at different layer heights, temperatures etc... which could and would affect the final surface finish which provides ridges for bacteria to live in. All that being said, if this is for personal use, I make cups for my children on my 3D printer. I either use ABS and acetone smooth it, or use any other filament and sand it then coat it with a silicone coating. I cannot and will not say if that is food-service safe, but I've killed less than one of my kids so far. I would definitely not offer such items commercially. I do a lot of product design at my work and that is a can of liability worms I would leave firmly sealed and stored in a cool, dark place.

I've had my Ultimaker 2 for about 13 months now and it has around 4700 printing hours. I don't know if that is a lot or pretty standard, but it does run most days and isn't a new out-of-the box machine anymore. While it does have a lot of hours, the prints are typically slow. I rarely exceed 40mm/s linear print speed and typically stay in the 20-30mm/s range. Many of my models are architectural in nature and I am a strong advocate that the fastest way of doubling print speed and maintaining quality is plugging in a second machine. In the last week I have been getting intermittent dramatic layer shifts. It will print fine most times, then suddenly the layers will shift between 3/16" and 1" in a single layer and it will continue printing. I have seen the shift occur in hour 23 of a 25 hour print, and on the first layer, so it seems like timing is pretty random. It appears the shift happens along both axes at the same time, but most dramatically along the Y. The shift seems to be fairly consistently Y- and X-, I have not noticed it ever being any other direction. I've checked grub screws, belt tension, head motion and all seems in order. The motion rods are wiped and oiled every Wednesday, or as needed between prints if any sticking is detected and stripped clean with isopropyl and re-oiled each Saturday. The motion feels smooth and equal in all directions. I was not expecting to see anything there as when I have had the machine get loose before, I typically see a gradual lean develop into layers shifting, not a sudden clean interruption and shift in the layer. I thought perhaps the endstop switches were at fault and have checked the mounting, the function of the contact switches, and looked at the wiring. I'm not a fan of the way the wiring to my Y axis stop passes between the belt and the side of the machine, but I do not see any indication of rubbing or any indication of either harness rubbing against the pulleys so I guess it's fine. I did not see any indications of damage further down the harness while I had the covers off to pull the motors to check the grub screws, either. I did try turning down current to the X-Y steppers as I have seen recommended on some of the UMO printers, but it seems to not make a difference. I didn't expect it would as the problem doesn't seem tied to print time which to me would indicate that it probably isn't a heat issue. Anything else I need to be looking at? I am still really thinking there may be something with the endstop switches. On my printers and other machines alike, when I see something dramatic and clean such as this I always look at any digital type on-off input that could be interrupting the process, as I typically see mechanical or heat buildup issues cause gradual shifts or changes, but a 1" shift is rather dramatic. Once it (hopefully!) finishes the print it is working on, I was thinking I might flip the machine over and check the endstop connections at the board, but I am guessing the endstops are normally open like many of my other machines so I don't think I will find anything there. Would it be crazy to run a few days with the endstops disconnected from the board once the head is zeroed to test the circuit and switch? If it helps, I can run some test prints tomorrow and post pics if it acts up. I can't really post my daily prints as they are for work and I would have to get permission to share them.

Realized I forgot to return and update. A re-load did seem to fix my problem, but I went back to running 15.04 (I run some Printrbots, as well so I keep a version installed). All went well with the earlier release. I ran that for a week before I talked the boss man in to springing for a S3D license for the office.

I have seen that before. I selected millimeters and exported. I know Sketchup isn't the most reliable .stl generator out there, so I imported the .stl to 123d Design and re-checked dimensions. The weird thing is, the same .stl sliced three times gave three different answers. The model is supposed to be 8-3/8" length. One is 8-1/16", one is 8-1/8", and the final is 8-1/4". I just sliced the model in Cura 15.04 and started it, then paused after the first couple layers and measured it and it seems to be scaled appropriately. I've got previous examples of this same model printed from the same .stl in the same program at the right scale, so I am not sure what exactly is going on. I thought maybe I'd thrown something off in the printer, but I printed a few Benchys and measured them against the dimensions online and everything seems correct there. I'll do some more checking with the current Cura and if I don't find anything, I think I'll re-install.

I am running Cura 15.06.03. We have been printing building components sliced through Cura on our Ultimaker, we've been running these about three months with no problem. This week, I suddenly have a major headache. None of my parts are fitting together all of a sudden. The models are made in Sketchup, and test fit in Sketchup. Before exporting the .stl, we are scaling them in Sketchup and checking the dimensions. After I bring them into Cura and slice them, I load them up on the Ultimaker and print, and they are typically smaller than they were in Sketchup. The building parts are modular, so we are basically just making changes to the same platform again and again, nothing we should be doing should be affecting the overall dimensions. Furthermore, I can re-slice the same .stl and it will return a different size the next print. I hate to admit, but we ran two or three of these models before I sat down to post-process and start painting and said "wait a second"... The differences are +/- 1/8", so they werent really apparent until we had them right next to each other. Wiped out a week's worth of printing. Is there something I could have done in Cura to cause this? One reason I like Cura is that it requires clicking a button to the side to do any scaling or rotating, so it's hard to do accidentally. I printed an old Benchy gcode I had on a SD card and measured it with calipers and it came out fine, so I am tentatively ruling out the printer developing problems. If anyone has any ideas, let me know. I sliced a model on Simplify3D this morning to double-check the printer itself. I'd really like to go back to using Cura, however, as the models have been coming out absolutely incredible and I would rather not change a thing if I can.