ttaiwo

@Dustin thanks for confirming this for me

I have been comparing the benefits of some process changes to designs printed on our Ultimaker S3 through tensile testing. I am using the Ultimaker TDS and similar specimens to one tested in their TDS to validate our tensile testing procedure. However, next to most mechanical property values, they have an additional ±value. I am assuming it is just the standard deviation of all the samples they tested. However, I want to confirm this as it could be a confidence interval or something else. I haven't found any mention in the forums, and it doesn't seem to be explained, at least in the PLA TDS. Thanks in advanced

Thanks for the suggestions I have been doing test prints since my last post using some of the suggestions and other things to try and solve the issues. Apart from reducing walls, top and bottom to zero and adjusting the infill direction I am pretty much using the stock normal 0.15mm layer print profile for the Ultimaker S3. In summary, what did not work: - Printing at a temperature of 220 degrees C - Print at 30mm/s - Print at 25mm/s What has seemed to help: - Drying the PLA in a dry box - Printing from a dry box The best result so far is: - Printing at 10mm/s (hence the delay in replying as these take 16hr +) So this is current where I am at the moment. So I have ordered some fresh Magenta, Blue and White Ultimaker PLA and will see if a fresh spool has this issue to see if it's a moisture issue. Printing directly from the dry box is not ideal because it restricts the filament path into the feeder, but drying it every couple of days is possible. Apart from trying a fresh filament spool, I am not sure what else to try. I found a forum mentioning a setting called Cura extrusion multiplier which sounds like this would help me with my issue but I cannot find this option in the printer settings I have found Flow Rate Compensation Factor and Flow Rate Compensation Max Extrusion under experimental however I am not sure what these are doing and how best to use them, any insight into these settings? Finally, I might try reducing the power of the part cooling fans as I am not doing overhangs etc. Thanks in advance

I gr5, Today I cleaned the print core using the hot pull and cold pull as instructed on the Ultimaker. I have swapped them around before but we have another Ultimaker S3 that has some bed levelling issues so I will swap a print core from there and order some brand new ones in the meantime. As I have recently swapped the print cores around the amount of filament and hours in use for both are: Print core 1 (swapped): Time hot = 38d 17h, Material amount = 975.92m Print core 2 (original): 113d 8h, Material amount = 2119.24m I tried using the move menu and it seemed responsive. I do not think the under-extrusion is significant enough to notice by my human standards. I have been using the stock speed profiles with little modification so I thought the machines could handle it too, I am just about to throw a print on at 220 degrees C so I will try the 3X slower print after.

Hi Dustin, Thank you for your suggestions. Currently, I'm using CURA 5.5, which features enhanced speed profiles for the Ultimaker S Series printers. These profiles reduce print times and if I am not mistaken one way they do that is by speeding up infills. However, the issue I'm facing was also present in CURA 5.4, which I believe predates these faster profiles. However if nothing else works I will revert to an older CURA version or reduce the print speed manually. I have previously adjusted the feeder tension to both 3/4 and full, starting from the assumed default halfway point. Unfortunately, this adjustment hasn't had any impact. Today, I updated the printer's firmware. While I'm certain it will not resolve the issue, it seemed worth a try. Additionally, I've cleaned both print cores and replaced the bowden tubes for print core 1. I've left the feeder tension at 3/4 for now and I'll conduct three test prints at the temperatures of 200°C, 210°C, and 220°C and will update you on the outcomes.

Hello, Firstly the parts I am printing are for conducting tensile testing. Therefore the printing choices may seem unusual for standard 3D printing, but they are essential for my tests. If I indicate that a proposed solution is not feasible, it could be due to these specific requirements. In the images provided, you can observe gaps in the magenta section of my specimens, which consist entirely of infill with no walls. The infill setting is on 'lines' at 100%, not connected, and aligned with the arrow's direction. I'm using an Ultimaker S3 with dual extrusion, where Printhead 1 uses Ultimaker Magenta PLA and Printhead 2 uses Ultimaker Blue PLA. Notably, Printhead 2 does not exhibit this defect. Specimens with significant gaps tend to crack across the specimen, perpendicular to the direction of the arrow, during loading. If a crack intersects a gap, it then travels along the gap before continuing across the specimen, resulting in a stair-like break, as shown in the final image. This issue could be impacting my test results. Efforts to resolve this include cleaning and adjusting the tension in Feeder 1, swapping print cores and materials, and increasing the line width from 0.4 to 0.45. Unfortunately, these steps have not eliminated the gaps. The frequency of this issue is causing me to discard every other print. I have yet to try printing at a higher temperature, which could affect my previous results. Calibrating the e-steps of Feeder 1/Extruder 1 on the Ultimaker S Series is another consideration, though I'm not sure it's possible. The specimen's total width (20mm) is a multiple of the line width (0.4mm), negating the possibility of mismatched dimensions being the cause too. I welcome any questions or suggestions from the community as I explore further solutions.