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Discuss any sort of mechanical stuff here: positioning systems, gears, extruding methods, etc.
Re: Z02 Z axis Sarrus linkage - 14 years ago
Took me a while to figure out too. Just type whatever wiki address you want into your web browser's address bar; instead of a 404 error, you get a page asking if you want to create a page there.by Wade - Look what I made!
Re: 
Looking for trashed parts. - 14 years ago
How about these? I have tons of failed parts. Mostly PLA, but there's a few ABS parts in there as well. Looks like it'll be about $14 to ship em in an envelope pack, but that'll take at least a week. Faster is more expensive. Let me know what you think - sent you an email too. Wadeby Wade - Singapore RUG
Re: Linear Motion Precision - 14 years ago
Those are subjective questions - how much resolution do you need? That will depend on what you want to do. Here's what's worked for me - 0.1 mm resolution, using a 0.5 mm filament, gets me enough resolution to make more repraps, including simple gear trains like this: Speed is the other limiting factor though - I have been running at 16 mm/s, and I find that it's pretty slow. It takes a weekby Wade - General
Re: Gen3 electronics mod for Mendel - 14 years ago
Ah, right! Now I see it - the top trace on the ICSP connector. Yeah, looks like they're different versions. Looking at the PDF's from subversion, I see that the photo with the A you've uploaded above is actually of the Motherboard v1.1. The toner-transfer image is v1.2, which is the latest. They probably wrote the docs with an earlier version, and didn't bother to update the photos. I'm acby Wade - Controllers
Re: Some questions on the electronics??? - 14 years ago
Regarding the I2C lines with Adrian's 5D firmware - I've just made a few test prints with a Darwin running the 5D firmware, and there's a bit of a hack in there right now. Adrian is using the I2C lines to control the extruder stepper, and the RS485 for everything else. It's just step and direction signals, no actual I2C, so you could probably swap out some different pins. I think the I2C linesby Wade - Controllers
Re: Gen3 electronics mod for Mendel - 14 years ago
Hey, not implying that you're an idiot, but what difference are you seeing there? Those images look the same to me. The jumper goes from the 4th pad on the TTL USB connector to the ICSP pad. Wadeby Wade - Controllers
Re: Increaasing z-axis torque - 14 years ago
How much current are you running the Z stepper on, and how fast are you trying to move it? The Z axis doesn't have to move too fast; I've got a Darwin that will do 3000 mm/min on the X and Y, but it doesn't like to go much above 150 mm/min on the Z, although I haven't optimized it yet. Since I only move the Z 0.3 mm at a time, it's not a big deal. I also shoot for about 1 A on the Z stepper, bby Wade - General
Re: Circular interpolation behavior - 14 years ago
Since we're starting from STL files, in which curves are approximated by a series of flat triangles, we never use curves, just a series of short straight lines. Curves or circles would be better, yes, but you're going to need a better file format than STL to work from then. And that's a whole new can of worms. But it would be great. One of the problems I'm having right now is that lots of sby Wade - Firmware - experimental, borrowed, and future
Re: North American Subsitutions - 14 years ago
Self tapping screws in plastic are great for single use assemblies, but if you have to disassemble it ever, you're better off going with trapped nuts or threaded metal inserts. The plastic threads don't hold up over time. Lots of details on this subject in Very few things on my reprap are assembled only once. I just pay extra for metric hardware; it beats having to redesign everything. Waby Wade - Mechanics
Re: Suppliers in Canada?? - 14 years ago
Khaled, check out Active Surplus on Queen St if haven't yet, and plan on spending some time there. I found many of the parts for my first Ddarwin there.by Wade - General
Re: RepRappable replacement for a worm gear? - 14 years ago
Wow, that setup makes my brain hurt! Pretty neat! I've been having some success with printed gears with a little less than a 5 mm circular pitch, and I think your planets have a circular pitch of about 3 mm, so I could almost try and print one of those. Maybe once I get my extruder and firmware tuned up. Here's a shot of my gears: Pretty rough still, but they are working so far. More tesby Wade - Mechanics
Re: Quad-Copter - 14 years ago
Hey, looks like fun! I have the electrics from a crashed up RTF li-po rc plane that could go ballistic; it's occurred to me that I should try and reprap a replacement airframe for it. Having spent a few years flying and crashing paragliders around the Rockies, I think I'll stay away from the paraplane stuff for now; ram air wings have a tendency to fold up mid flight right when things get intby Wade - Let's design something! (I've got an idea ...)
Re: Extruder drive further questions on the extruder drive. - 14 years ago
BodgeIt, Nophead has a great post where he tested the pull of various systems using a socket wrench instead of a weak motor. Here's the link: Here's a cut and paste of the results: QuoteNophead I tried the M3 pulley and that was better still, raising PCL to 8Kg. Here is a summary of all the tests: - PCL HDPE ABS PLA 4mm splined shaft 2.5 Kg 3.0 Kg 5.0 Kg 7.5by Wade - Reprappers
Re: Extruder drive further questions on the extruder drive. - 14 years ago
I used a small 11 tooth gear, roughly 7mm diameter to get 5.5 kg of pull. Photos of it are here: Click on the second photo a few times, and you'll get a super blown up version of the photo, or just click here: It's the little brass gear in the middle. The teeth themselves cause a fair bit of acceleration and deceleration as they grip the filament, which might be a problem. I've made aby Wade - Reprappers
Re: RepRappable replacement for a worm gear? - 14 years ago
My gears still come out a bit bigger than designed, which is easy to adjust for in a simple spur gear arrangement, but it would take a few tries to get the gear sized just right for a planetary gear. It does look promising though! I also like the harmonic drive gear - That might be a bit simpler to reprap; two annular rings, one thinner flexible gear, and maybe a pair of 624 bearings on a bby Wade - Mechanics
Re: Extruder 2.2 stepper not turning on - 14 years ago
Did you run the SDA and SCL lines from the motherboard to the extruder? It's a bit of a messy hack, but it keeps the stepper timing all on one CPU. Watch out for noise on those lines though! Wadeby Wade - Firmware - mainstream and related support
Re: Mendel Extruder stepper motor gear or no gear that is the question?
- 14 years ago
Yeah, the 0.5 mm extruded filament length resolution on that one works out to about 0.7 mm; but my current extruder can't start or stop in less than 10 mm, so I don't think it's too much of an issue, yet. This should still be way better than the old one. For now I just have Skeinforge tweaked to minimize starts and stops. Plus most of my extruders so far seem to act like low pass filters - asby Wade - Reprappers
Re: Mendel Extruder stepper motor gear or no gear that is the question? - 14 years ago
With some better printed gears, I managed to get 5.5 kg of pull on the filament before the pinchwheel started slipping, details here: Wadeby Wade - Reprappers
Re: NEMA17 Stepper motor for extruder? - 14 years ago
I tried some old surplus versions of that stepper - at 864 g*cm, they have about 1/5th of the torque you need for a decent direct drive pinch wheel extruder. I could only get it to extruder 1 or 2 mm^3/s of PLA through a 1 mm nozzle. I've been working on gearing down the 5 kg*cm Kysan stepper motors I've got - so far it looks promising. Details here: Wadeby Wade - Mechanics
Re: Canadian Suppliers? - 14 years ago
spaztik, if you know of a Kysan depot in Vancouver, I'd love to hear about it. I had to order in some 5 kg*cm Kysan Nema 17 steppers in from China, and it took almost 2 months. I do have a couple extra, send me a pm if you want any. They have flats on the shafts, so they aren't great for the standard extruder design, but I've been playing with a geared extruder that might work out. Photo of iby Wade - General
Re: Mendel Extruder stepper motor gear or no gear that is the question? - 14 years ago
Just a heads up - I also built a couple of the Mendel splined extruders, and I wasn't able to get enough torque out of the surplus steppers I had around. They were pretty weak Nema 17's though. Now I'm experimenting with a geared version; although my printed gears are not quite ready for primetime yet. Looks like I'm going to have some issues transferring the output torque from the driven gearby Wade - Reprappers
Re: Mold and pour mendel parts - 14 years ago
Murd, that is quite cool! We really should get a section of the wiki up about moulding, as there seem to be quite a few people heading that way. Wadeby Wade - Casting and Moldmaking Working Group
Re: z axis torque - 14 years ago
Check the squareness of your Z rods as well; they need to be parallel to the vertical smooth rods to prevent binding as the bed travels up and down. A couple mm off on the bed hole dimensions can mean that your Z axis is trapezoidal instead of square, which will cause binding at certain heights. Also check the tightness of the Z rods on the lower corner blocks and the z tie brackets - keep em pby Wade - Mechanics
Re: Mold and pour mendel parts - 14 years ago
I've got a set of hand cast resin Darwin parts from Bits from Bytes in the UK. Every part that needed a trapped nut, they moulded in an M5 nut to provide the threads. There's quite a few of them, roughly 50 I'd guess in an entire Darwin. Probably one of the reasons the parts cost so much. It looked like they used bolts to position the nuts in the casting, then simply unscrewed the bolt when tby Wade - Casting and Moldmaking Working Group
Re: Stepper Motor - 14 years ago
I've got some 5 kg*cm Nema 17 steppers from Kysan in Vancouver, but they have flats on the shafts; they won't work for a knurled extruder. I'm looking for a really small gear to mount on them, but haven't found one small enough yet. Wadeby Wade - Reprappers
Re: what thread size to use for threaded drive system - 14 years ago
I'd avoid using threaded drives, as they're usually pretty slow for a Reprap. We shoot for 0.1 mm / step resolution, which is pretty easy with a belt drive and 200 step steppers. If you were to use an M3 threaded drive with a 200 step stepper, you'd get 0.0025 steps per mm, and a top speed of around 2 mm/s (rough estimation). My Darwin runs at 16 mm/s, and takes a full week of extrusion time tby Wade - Mechanics
Re: Reduce Mendel to 8 Threaded Rod Bars, less scrap! - 14 years ago
Yeah, my printed Mendel uses the two extra M8 rods on the Z axis. I would guess that the Z bearing plates were split to fit on the Makerbot build area; thus the two extra rods. Easier to avoid warping problems too.by Wade - General
Re: SourceForge OBJRCT FILE - Please Help - 14 years ago
Any particular reason you want to stick with the Darwin? I've built 2 Darwins and one Mendel, and the Mendel was way easier to work with so far. The Darwin part counts can be found here: Click on the + symbol next to the Printed Part heading. Also, you can get away without every single one of those parts - here's a listing of what I built for the last Darwin I printed out. I generally use Mby Wade - Mechanics
Re: McMaster pulleys + belt - 14 years ago
As long as they match your steppers, you should be fine. I used 20 tooth 1/4" bore MXL pulleys on my Darwin's X and Y, but not from McMaster, and so far they've been great. Just switch out the 8 mm Y drive shaft for a 1/4" shaft and you're golden. On the Z, 60 tooth 1/4" bore MXL pullies tap out to M8 nicely. A 1/4 " coupler will make life easier too. Wadeby Wade - Mechanics
Re: Extremely Low Torque to Extruder Stepper Motor - 14 years ago
The Makerbot DC motor, the Kysan 37 mm DC Gearmotor, is listed as having 8.47 kg*cm of torque. That's 0.83 Nm, so it's about 3 times the torque of their Nema 17 motor. I've ordered up some 5 kg*cm Kysan Nema 17 steppers to try out for stepper based extruders; the part number is 2BYGH4803; I'll let you know how they go. I'm also noodling around with a geared extruder head, similar to Nophead'sby Wade - Mechanics