Quotemikefiatx19 Still banging my head on a wall here. EEPROM is enabled in Marlin but the offset is not making any difference to my prints. The head is just dragging through the plastic. As a test I even set the head offset to M555 Z4 as i knew this should be too high, the program just ignores it though. Hi Mike, I scratched my head over the z offset for several evenings. I just added a Zby CellJeffe - Smart_Rap
My SmartRap (aka "Strudy") is running like a well-oiled precision machine - about as good as the Makergear M2 my colleague just bought out of jealousy. :-) Here she is proudly printing her eventual offspring. a SnapRap strut stack -- now somewhere around version 4 or 5-ish.by CellJeffe - Smart_Rap
I am still lurking! I have a busier family life now that the wife and pets finally been able to join me in the new location. So, I no longer have the "bachelor" life to spend all hours with my 3D printer. But I just fired up my SmartRap today to test out some new ideas for the PVC SnapRap. Hmm, Judging by the groans, my SnapRap needs regreasing after three weeks idle.by CellJeffe - Smart_Rap
Quoteregpye If the magnets are mounted on the bed plate, that plate would also have to be positioned in exactly the same place each time as well, or there will be bed crashes for sure. I guess all of these things can be worked out. Yes. The existing servoless Z enstop switch would probably need to be kept to sense head crashes. Of course an alternative would be a piezo-resistive sensor on one ofby CellJeffe - Smart_Rap
I haven't looked to much at inductive sensors on an aluminum plate, but an arduino can easily drive a hall effect sensor. I am thinking about a hall effect sensor on the bottom of the head and three magnets glued to the underside of the glass plate such that they form a right angle. The sensor might be useful for both bed leveling and skew. Wave the head in XY over where the magnets ought to be tby CellJeffe - Smart_Rap
Quoteregpye Why not use a straight rack? That would overcome that problem. Easier to print out too. A straight involute gear (straight rack) generates positional error as the contact is transferred stepwise from tooth to tooth -- so it produces bad resolution. A helical gear maintains more continuous contact that slides along the slope as motion is transferred from tooth to tooth. They get muchby CellJeffe - Smart_Rap
Quotecristian QuoteBackEMF I think it would be great to be able to slap together 3 axis and hit the print button, let the machine figure out the wonkeyness and spit out a perfect print. That woudl be great, but even after thinking about it for some time I cannot find ways to detect automatically skew. It may probably be detected without printing a calibration object by using some fanciful measureby CellJeffe - Smart_Rap
Someone in another forum mentioned "sinusoidal" herringbone gears. That has me intrigued. Presumably, the helical gear mesh path develops sinusoidal error as the meshing teeth progress along the slant. A sinusoidal mesh pattern might compensate -- double it to a herringbone pattern to cancel the axial thrust. Unfortunately, the only thing I can find on sinusoidal herringbone gears are a set of paby CellJeffe - Smart_Rap
Those are all great resources, thank you! The defensive publication or the research disclosure are probably the routes I will end up going down, possibly to coincide with a manuscript... My only concern is that these sub-patents do not integrate well into a curriculum vitae/resume (thus the publication). Mine needs all the help it can get at the moment... I was also considering the opportunitby CellJeffe - General
I know that the RepRap community has been adverse to patenting, but perhaps that needs to change in light of the MakerBot "patent ALL the Thingiverse things" fiasco. In light of that, say that I have come up with a new widget. Say this widget would be of benefit to the RepRap community and I would like to keep said widget open source. Of course, if MakerBot or some other company got wind of saidby CellJeffe - General
Quotecristian It seems to me that the autolevel matrix cannot detect everything. It will detect correctly the Y-Z skew I think, however for the X-Z skew the autolevel will only correct the difference of skew between the bed and the X/Z rods. Of course the X/Z rods skew should be negligible unless the plate_x is faulty. Nevertheless I would like to measure it to be sure. If there is Z skew, it shby CellJeffe - Smart_Rap
Quotecristian Thanks CellJeffe! Have you measured skew for Z axis too? Yes. Theoretically, the existing autolevel matrix corrects for Z-axis skew. Theoretically. It would be nice to see other smartrap users verify that theory . Here are my calibration files and the openscad programs that generate them. XY Skew calibration Print out the calibration object (or generate from ). Mark the positby CellJeffe - Smart_Rap
Short answer: The autoleveling code already calculates a rotation matrix so that Z is always perpendicular to the actual XY plane. I added an XY skew transformation matrix to the bed-leveling matrix through a simple matrix multiplication. Long Answer: Linear Algebra Time! The existing bed leveling algorithm calculates a 3x3 rotation matrix that can turn any 3D coordinate (x,y,z) into another 3Dby CellJeffe - Smart_Rap
My solution to the X-Y skew problem was to add a skew matrix to the three-point auto-leveling matrix: --- Configuration.h --- #define SKEW_AXES // Can add a scew to the x, y or both axes to compensate for #ifdef SKEW_AXES // Adds an X and/or Y axis scew to the auto level matrix. Can compensate for non-rectangular cartesian problems #define X_SKEW_ANGLE_DEG 0.00 // Shift the x axisby CellJeffe - Smart_Rap
Quoteduranza Wow.. Very very nice... Ditto! Absolutely fantastic!by CellJeffe - Smart_Rap
I just ordered another J-head mk V for my smartrap, but how do you like the J-head Light? I am considering them for my next printer project.by CellJeffe - Smart_Rap
Wow! Now I need another hot end... Quick question: Would one monster 40mm fan be enough to cool two side-by-side J-heads? A 40x40x10mm fan would probably be too low air-flow, but I have a monster 40x40x25mm CPU cooler fan laying around that actually cooled down a single head too much! But it might just balance out 2 heads.by CellJeffe - Smart_Rap
Quoteregpye Yes I noticed that you followed my idea and used a similar design. Works well doesn't it? When I get it all finished I will post the files for others to use if they want. Yes indeed, it works well! The only thing I added to the concept was to make 4 thin, protruding ribs between the mount and lever arm. They keep the two parts at a fixed distance during rotation, but with a much smalby CellJeffe - Smart_Rap
What a difference a fan makes! I added a bed fan mount to my servoless j-head. So far, the prints are much improved! I was having some Z-axis issues with cables snagging, so will not post photos of the resulting 5-mm steps yet. Suffice it to say that my bridges are now perfect, as are the top layers! I was correct that there was enough room behind the x-end for a bed fan. It took a couple of iteby CellJeffe - Smart_Rap
QuoteMelT It's just that celljeffe's fan is only 40mm so it looks like it's just big enough to blow on the cold end. I'm having some level of success on my setup but I believe the best would be a dual fan setup. One dedicated for cold end and a ducted one for the print because as you will discover, you will need cooling only on some parts of the print. I have yet to see someone do this on smaby CellJeffe - Smart_Rap
QuoteMrDoctorDIV QuoteCellJeffe However, the design does have the advantage of only 3 motors for full X-Y-Z I know of more 3 motor cartesians than 4 motor, where are you grabbing this information? I've got a 3 motor cart. myself and have no issue related to not enough motors. Yeah, good call. I was mostly thinking of Prusa/Mendel-style cartesians when I wrote that. In fact, I have a 3-axis-motorby CellJeffe - Delta Machines
Hmm. I switch over to all rack-and-pinion last night (and a 0.4.9 update!) and decided to do some speed tests using the speed multiplier of Repetier (base settings Perimeters: 30mm/s, Infills: 40mm/s). Speed was not the problem. The printer could easily go 150% to 200% faster than the base settings. After some sleuthing, I determined that cooling was the main problem with increased speed! Bothby CellJeffe - Smart_Rap
I've been using the shorter 0.48/0.49 bearing holders for the X axis. There is plenty of clearance now between the bearings and rack/pinion. In fact the rack fits much better there than the GT2 tensioning bearing!by CellJeffe - Smart_Rap
I am using the split rack from the SmartRap github models - with a 5mm threaded rod through the middle and 5mm nuts on either end of the rack. I purposefully printed some test cubes and thin walled boxes so that the rack joint was directly in the middle of the printed object. I could not see any sign of the joint between the two rack halves of any of the printed objects! I also switched to 1 perby CellJeffe - Smart_Rap
I've been sticking to Perimeters: 30mm/s, Infills: 40mm/s.by CellJeffe - Smart_Rap
Yes. I definitely need three arms per side to keep things parallel. Speed will certainly also be an issue with the moving build platform. However, the design does have the advantage of only 3 motors for full X-Y-Z motion instead of 4 motors of a more traditional cartesian style printer. Instead of one motor/rail/belt for the X platform, two linear rails and 2 motors/lead screws in Z and one motoby CellJeffe - Delta Machines
Has anyone else tried out the herringbone rack and pinion system on their smart rap? I tried out the GT2 belt system using some of the STLs updated on github. The X axis belt kept slipping off of the tensioner bearing, so I replaced the X axis belt with the printed herringbone rack and pinion. My Y axis is still setup as a GT2 belt. I must say that the rack & pinion is extremely smooth! I caby CellJeffe - Smart_Rap
wtf indeed! I'm playing around with linear rails made from PVC+thin steel rod (not on yet)+printed strut+zip ties. This was an impromptu beam bending test. :-)by CellJeffe - Delta Machines
Thanks all. Although I am surprised that I have not seen other hybrid deltas. I'm still working out some other fun design elements for this printer...by CellJeffe - Delta Machines
One would actually need 3 connections on at least one side to keep the extruder parallel to the plate. Two of the delta connecting rods would always form a parallelogram with the extruder plate. The other side could be 180 degree rotationally symmetric, so 6 arms in all between the sides and the extruder plate to keep things parallel. And it would definitely need delta-style extra hight to get cby CellJeffe - Delta Machines