lars86

Awesome! Thanks for sticking with it and getting some good results. I should make some higher overlap versions too since everything improved up to .4 for me too.

Very weird! Just in your little code snippet, I did the math by hand, and found it to be off slightly. But my math tells me it isn't enough to cause the whole issue though. Did it seem to start the print extruding correctly? You could always back down the multiplier by maybe 10%. So, x2.55

I think you are farther along than you give yourself credit for, but are just tripping up on some details. (and you are still the only one who has bothered to try) It looks like your print is starting with a .15mm layer, not 0.1mm. So if you tried to do calcs on the first layer code, results will be skewed. I did a distance calculation from your code, and divided the extruded distance, by the movement distance and got 0.0166265 mm filament / mm travel. This is 2.65175... greater than the same value in my code. Exactly what I expected to see. I think something must have gone wrong in your script, originally. You should just be able to take my code and multiply all E values by 2.65

It sounds like you are just running a firmware that does not support live flow override (bummer). Here is the STL file: https://dl.dropboxusercontent.com/u/60958586/Test.stl I redid the multiplier calculation, and the factor should actually be 2.65x. The first calc was using the nominal 3mm size, but in reality I am printing with 2.85mm. You really should just be able to take all EXXX.XXX values and multiply by 2.65

Hmmm, okay. Let's get to the bottom of this. Are you running Marlin firmware? Do you have a 0.4mm nozzle? I just ran the beginning of the gcode, and the M221 S293 line sets the "Flow" parameter inside the "tune" menu, to 293%; just as expected. What made you think it did nothing? All the extrusion distances in the gcode are absolute, so to normalize volumetric flow, for a given length, we just need to correct for cross-sectional area of the filament. Pi cancels out, so we just need a ratio of r1^2 / r2^2 to get the multiplier. I think the math is good. Are you sure your hot end isn't clogged, or the temperatures wrong for the material you are printing? I hand edited these files to add the overlap. This was a preliminary test to justify developing a feature in Cura.

Ah, okay! So, it's not the "feed rates", but the extrusion rate (also a feed rate). Doing a quick calculation, it looks like you need to push 1.75mm filament 2.939 times faster for the same flow rate. I edited the gcode files to add this flow rate multiplier in, and hopefully it is without the allowable range. I also put in a 50mm shift in both X and Y, to bring the print away from the edge for you. I like printing near the back corner of my 205mm build plate for less vibration. Give these a try and let me know: https://dl.dropboxusercontent.com/u/60958586/Seam_Overlap_1.75mm.rar Thanks!

Hurry up and try it already!

Results, yes. But not joining the conversation!

50+ views and no one cares about invisible perimeter seams?!?!?

Hi guys, In the pursuit of the highest quality prints possible, I am trying to minimize the appearance of the perimeter seam. First off, as a survey: Would you say that your seams generally bulge outwards, pucker inwards, or both? (sometimes the seam looks like mini cleavage, with slight bulges on either side of a small divot) (It is definitely best to print with the seam location set to "back" or "aligned", so that you can see more clearly.) What machine are you using? What slicer and version are you using? For me, the seam is a slight dimple in the print skin, using the new Cura 2.1.2 (which is awesome if you haven't tried it!). I felt that this could be addressed by adding an overlap between the start and end points of the perimeter. On Github, we hypothesized, and disagreed on why it would or wouldn't work. So I decided to just test it experimentally. I made a very simple test of a hollow test cylinder (just a few perimeter loops): The control is without any modification Overlap_0.2 is the above file, with additional print moves added to the end of each perimeter loop, which extend the loop by 0.2mm, in the correct direction. Followed by 0.4mm, and 0.6mm overlap files. Here are the results on my printer (a heavily modified UM): Full size: Results I would love to get a good spread of results , across different machines, and that's where you guys come in. As long as you are running a 0.4mm nozzle, this code should print just fine with PLA. If you want to print other material, feel free to change the temp (just make it equal across the tests). Just make sure to label the prints as they come off the machine. If you are able to get decent quality photos of the tests, that would be awesome. I used a piece of tape to hold them all together for my photo, which definitely helps the comparison. Even if you struggle to get an up close photo, some descriptive feedback would be helpful too. Just describe what you see when looking at the seams, and checking them with your fingernail. If we can demonstrate that this provides improvement for most people, I think it will be added to Cura. Here are the gcode files: For Ultimaker Original (and other Reprap printers) running 3mm filament: https://dl.dropboxusercontent.com/u/60958586/Seam_Overlap.rar For Ultimaker 2: https://dl.dropboxusercontent.com/u/60958586/Seam_Overlap_UM2.rar For Ultimaker Original (and other Reprap printers) running 1.75mm filament: https://dl.dropboxusercontent.com/u/60958586/Seam_Overlap_1.75mm.rar (These files use the flow override firmware function to convert filament diameter) https://dl.dropboxusercontent.com/u/60958586/Seam%20Overlap%201.75mm.zip (These files were modified by DaHai8 to convert by modifying extrusion distances)

I might try to implement a new print head design which decouples the two bearings, allowing you to square both shafts, then lock the print head in position last.

I'm glad things improved! The two likely suspects are: -Bushing deformation -Cross-shaft squaring issue On the bushings, this is why I made the bushing clamp an independent piece of hardware. The bushing should slide into the XY block very easily. If not, you should sand the ID of the block. From there, you only want enough tension on the clamp screw to make sure the bushing doesn't slide out. This is VERY little force. Push the bushing back and forth within the XY block as you slowly tighten. The unintuitive part: you should still be able to move the bushing in the block without much effort! It just needs to take more force than the bushing sliding over the rod, which is very little. As an extra factor of safety, you can add a drop of superglue between the bushing and block once it's all together. On the rod squareness, from my description on the XY block page: "I actually discovered that my printed print-head was holding the 6mm shafts slightly out of square, so forcing them square to the 8mm shafts actually induced bind! You can simply loosen the belt clamps on two opposing XY blocks, move the print head back and forth by hand and reclamp." I would recommend using the squares to set the relative position of only one rod. Then use the above technique to lock the other rod in position. Ideally, both being square, is also the lowest friction position. But I think allowing a very slight amount of out-of-square, to lower bind substantially, is a worthy compromise.

What? New development? The advance stuff has been around for years and some printers use it routinely (they need it!) but I haven't heard about any *new* development. https://github.com/MarlinFirmware/MarlinDev/issues/402 The advance function in Marlin has been broken since I got into printing. Someone has already figured out why it isn't working and fixed it. But we've got a discussion going on creating a better implementation.

Droooool I REALLY want to upgrade the electronics on my printer, and the Replicape/BBB looks like a really powerful combo. My biggest concern with that, is the firmware. I really like Marlin, and am excited about some of the new development work in it for extruder advance.

On that note, wouldn't doubling the steps / mm, and halving the microstepping be a wash as far as the Arduino is concerned, in steps / sec output?

Awesome, thank you for the insight! So, is that to say the drivers are only safely capable of 300 mm/s * 78.7402 steps/mm = 23622 steps / sec? I'm guess that after switching X and Y to these 0.9* / step motors, I can switch from 1/16 microstepping to 1/8.

Anyone? The rated current per phase of 1.68A * 2 phases = 3.36A, seems reasonable for the geared stepper. Is the 2.0A / phase on the other motors too high for the UltiStepper driver?

...and while I'm at it, switching in these for X and Y: http://us.stepperonline.com/09deg-nema-17-bipolar-stepper-motor-2a-46ncm-17hm192004s-p-122.html

Hi guys, Would this stepper plug and play with the UMO stepper drivers? http://www.omc-stepperonline.com/gear-ratio-51-planetary-gearbox-high-torque-nema-17-stepper-17hs191684spg5-p-40.html I'd like to design a new extruder drive around it, or something similar. Thanks!

There are holes in the back face to install M3 bolts, which trigger the switches.

Hey @Rudy102, I went ahead and published a version for you. In return. you just have to let me know how the Igus bushings compare! I've been using a lot of their products lately, and even printed some of their filament. Good stuff. I also added a new tighter belt clamp variant. I think some people have had issues with a lack of clamping force, which could be caused by layer height settings causing the clamp to be too thin. Thanks a lot @lars86! I will print them and tell You how they came out. Unfortunatelly my ultimaker is still in building phase (waiting for motherboard). Im using Igus WSM-0810-15 bushings with their AWMP-08 rods. The issue is that the bushings should be fitted with H7, otherway there will be some play. I have actually found that even in the proper press fit, their bushings are closer to the top of quoted tolerance. Hopefully you can get enough out of the clamping bolt to snug it up well and tune the fit. That bolts threads into a real nut, so you should be able to clamp pretty hard. You might also be able to source shafts with a bigger nominal size that fit nicely. Are you worried at all about extra deflection from using aluminum shafts? Well, it's not going to work. I have returned the igus shafts and bushings, the fit is too lose. The only way to go with igus is to press fit the bushings with H7 fitting, which I won't be able to get with printed parts :/ Im sticking to original bushings on 8mm shafts, but I will give a shot for igus RJMP 6mm on print head with their rods. You should email an igus rep. They are really helpful, and might have an easy solution, that doesn't require a press fit.

That sucks.

Hey @Rudy102, I went ahead and published a version for you. In return. you just have to let me know how the Igus bushings compare! I've been using a lot of their products lately, and even printed some of their filament. Good stuff. I also added a new tighter belt clamp variant. I think some people have had issues with a lack of clamping force, which could be caused by layer height settings causing the clamp to be too thin. Thanks a lot @lars86! I will print them and tell You how they came out. Unfortunatelly my ultimaker is still in building phase (waiting for motherboard). Im using Igus WSM-0810-15 bushings with their AWMP-08 rods. The issue is that the bushings should be fitted with H7, otherway there will be some play. I have actually found that even in the proper press fit, their bushings are closer to the top of quoted tolerance. Hopefully you can get enough out of the clamping bolt to snug it up well and tune the fit. That bolts threads into a real nut, so you should be able to clamp pretty hard. You might also be able to source shafts with a bigger nominal size that fit nicely. Are you worried at all about extra deflection from using aluminum shafts?

After thinking about it some more, I can see the potential for layer height settings causing too thin a clamp thickness. I published a tighter clamp variant, if you want to give it a try.

Hey @Rudy102, I went ahead and published a version for you. In return. you just have to let me know how the Igus bushings compare! I've been using a lot of their products lately, and even printed some of their filament. Good stuff. I also added a new tighter belt clamp variant. I think some people have had issues with a lack of clamping force, which could be caused by layer height settings causing the clamp to be too thin.