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Anything related to printer controllers not being Duet, RAMPS or Sanguinololu: microprocessors, motor and heater driver circuitry, gEDA/KiCAD issues, soldering tips, etc.
Re: LISA Simpson Take 2 - 10 years ago
I think that moving the supports in takes care of most of the footprint issues. If you pack it in to tight, getting the print out of the machine will be a hassle. A max height / max diameter cylinder will be interesting enough to remove with a sunken print surface. Adding another tight fit isn't going to be very user friendly. ------------ So how long are the lead screws on this version? Theyby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
Ok, The outer wall of the barrel of the flange nut to the high point in the thread is ~ 0.160". That's going by what I can measure on one sample with a dial caliper. (you might have another 0.020) A 10-32 tap hole is 5/32 on my little chart. That's 0.156" . That's going to be a bit close. Looks like McMaster Carr has them down to #4. That would be a 3/32" tap hole. The thread has a .112" majby uncle_bob - Delta Machines
Re: LISA Simpson Take 2 - 10 years ago
I have sourced some of the aluminum tube that I suggested on the other design. That stuff is *heavy*. It's also a bit exciting to cut. The PVC is probably a better way to go for a generic design.by uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
My guess is that you would have to play a bit with springs and tapers. The data for that nut shows they cut the load rating from 90 lb down to 25 doing what they did. That suggests they are doing some pretty major chopping on the part. Not a trivial thing to do. For a one off printer, I'm not sure you would save any money. Depending on how the rest of the printer is set up you might / might not gby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
To really do the tension right, I suspect you need a spring to compress the cut end of the nut. With a static adjuster (like a NPT bushing) you are depending on the flex of the nut to ride out the inevitable irregular parts of the shaft. The better the spring does it's job, the less wear on the nut. Coming up with a wrap around spring that has the right spring constant could be a bit interestingby uncle_bob - Delta Machines
Re: LISA Simpson Take 2 - 10 years ago
Looks cool! 1) When you womp the big circle out of the middle plate, you reduce it's stiffness a bit. Do you think it still will be good enough to keep the screws all in line? 2) You can print the part the rides on the arm so the pivot point is a bit higher. That *may* give you more run length on the drive screw. Unless you intend to drive the top into the upper plate that would reduce the valuby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
There's never a design path that's all good or all bad. The cost of the lead screws (with some thread designs) is fairly high. That can drive you to a compromise that shortens the screws. In my case it drove me to a cheaper thread design screw. That made the cost delta associated with long screws pretty minor. No matter what you do for rods, you still have the issue of nuts. I'm doing all the aby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
1) If you put the motors on top, you need something to terminate the short lead screws into. 2) Most of the torque and force is on the plate that has the motors and screws in common. That would mean a fairly heavy top plate. 3) If all the electronics and control are going to be closely coupled to the motors, they would go up on top as well. Same thing for the power supply. Most of that simpby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
Flatness: A lot depends on how thin a first layer you are trying to print. If I stick with something in the 0.2 to 0.3 mm thick first layer, a flatness of 0.02 mm (slightly under .001") would be ideal. Anything over 0.01" will be difficult to use. That would be a total error over the print area compared to what ever I'm calling the Z zero plane. Any bump or pit that's < 0.01" dia probably doby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
At this point I'm not to concerned about mirror finish as much as I'm concerned about keeping the surface flat. I'll probably keep it in the packaging until I'm ready to mount it and give it a good soap and water scrub then. If I can't pick a "good side" once I get the dirt all off of it, I'll probably go shopping for some Flitz. Thanks!by uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
The 18+" aluminum disk came in today. A 34+ lb lump of aluminum is ... heavy. The surface finish is quite good. There's a bit of dirt and a minor scratch here and there. The streaks in the picture are just dirt. I'd say it's as good a printing surface as anything else out there. I'm not sure how well it would stand up to having plastic scraped off of it with a paint scraper. Other than that iby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
Parts like the CNC site listed would indeed work for the stepper to drive shaft *if* I wasn't working with such odd diameters. Going from 3/4" to 8mm is not common enough to be a stocked (or even an optional) item for any of the guys I have found. ---------------- Parts are beginning to pile up in odd corners around the house. As I move them from corner to corner .. they are heavy. I probablyby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
I *think* I want to have the arm take off from as close to the un-flanged end of the nut as possible. That would give me the max usable length on the drive screw. Given that this is a 5' screw I may be over thinking a bit here. If the takeoff is on that end, playing with the flanged nut is going to be a bit involved. The arm joint will take up at least 1" of the nut and more likely 1.5". There isby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
Backlash: Seems like there is a simple / high cost solution to the problem. Set up the flanged nuts back to back with the bolts as previously described. Instead of spacing them with nuts and doing a lot of fiddling, put a fairly solid spring on each of the bolts. The pressure required to zero them out is not all that great. A finger squeeze between the flanges will get the play down to the pointby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
The weight of the system goes up as it gets bigger. There's enough weight on the nuts to seat them pretty well in the threads. Since the weight is sort of a cube thing (ignoring going to aluminum or cedar), the self correction will scale up. The tapping and set screw approach probably is more practical with the bronze nuts than with the nylon ones. With the nylon you probably need to tap both tby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
Circular objects: If you take a look at the picture of the printed ring, it's got three lobes on it. You have three drive screws / 3 arms / 3 hub arms .... Think of it as many chances for things to stretch or shrink along each of the 3 drive axis. You still have distortion it's just not directly in X, Y, and Z. Moving the tool in a circle is just as difficult as moving it in pure X, Y, or Z. Theby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
After playing a bit more with the nuts, one of the things that does indeed need to scale on a larger printer is the "stuff" on the shaft that reduces backlash and tip. I see three basic routes, each with a bunch of sub routes: 1) Use the flanged plastic nut and a longer printed structure. (Scale up the base design). 2) Run a pair of plastic nuts back to back. Space the second drive nut down theby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
Floating Work Plate: No I have not really worked out all the details on this, but ... Rather than putting the work plate up on springs and bolts, why not use gravity? Hang the work plate below the mid plate. No crazy 900 lb springs. Gravity is fairly reliable. Suspend the work plate on three screws. Tweak them as needed to do first order leveling. I suspect the sunken work plate idea will beby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
With one of these, getting the "real" numbers into the correction code is going to be vital. The errors you see are not all going to be "X is to long, change steps on X" sort of errors. I suspect it will take some time to get it all dialed in. I would *guess* that printing a flat plate would be one of the first things to do and check. Check it for uniform thickness and get that dialed in first.by uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
I've gotten a lot of stuff like this in the same sort of tubes. These guys are the first ones I've seen that put them together so you can't just pull them apart. ............. Well the screwdriver and a modest amount of blood got it open..... The nuts all work with the screws. There's a bit more play than I'd expected. Without putting a dial indicator on it I'm guessing. I'd say the nuts haveby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
First print: Very cool !!!! Roton: Is there some secret sauce approach to opening the tube that Roton ships the shafts in? As far as I can see, my next step is to go down to the band saw ....by uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
Solder: I do a lot of soldering. You need to get the metal good and hot for the stuff to stick properly. Simple contact with the hot metal is not enough to give you a good joint. The temperatures involved are well above where the motor starts to get bothered. Torque: My main concern on torque is for acceleration and deceleration. I agree that the "smooth running" torque is quite low, even on aby uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
I've never understood if the main concern is "crud" or if it's straight impact damage due to the induced vibration. Since the gizmo is magnetic, it will grab on to any bit of this or that. Of course that's true if you bolt one to a CNC as well. I do believe I've seen at least one being used on a CNC...(in say the last 5 minutes).by uncle_bob - Delta Machines
Re: LISA Simpson - 10 years ago
Flat on shaft: One thing you see a *lot* of warnings about on motor data sheets is - "do not machine the shaft, you will damage the bearings". You could indeed pull the motors apart and then do the machining. That probably also voids the warranty. Apparently keeping everything happy magnetically as you do this can be a problem. Even with the flats, there's still a bit of torque involved. There'sby uncle_bob - Delta Machines
Re: Auto touch Z end-stop - 10 years ago
Before everybody goes crazy for this - consider the accuracy. A normal microswitch has an snap action for a reason. A simple contact does not have that. You need very good contact repeatability to make the bed leveling work.by uncle_bob - General Mendel Topics
Re: i3 Single Sheet Thickness - 10 years ago
If anything, I would go even thicker on the plate if possible. The minimum hole diameter is going to depend a lot on the water jet machine being used. I would check with the guy running it and see how small a hole they can do accurately. You may wind up hand drilling all the holes from scratch.by uncle_bob - General Mendel Topics
Re: RAMPS for Due! - 10 years ago
I'm not a big fan of series diodes. You paid good money for that power and now you are just throwing it away . There are some pretty cheap D2PAK dual diodes out there with big current ratings. The big problem is the area they take up on the board.by uncle_bob - Controllers
Re: Internal Holes too small in nearly all Slicers - 10 years ago
The other approach is to print them and then drill them. A lot depends on the end application.by uncle_bob - General Mendel Topics
Re: Help! Prusa i3 Hotend Snagging on Prints - 10 years ago
Once the filament gets moist, a dry out in a warm oven (or something similar) is about the only way to dry it out. Something in the 5 to 10 hour range at a temperature as high as the filament will tolerate should do the trick.by uncle_bob - General Mendel Topics
Re: extruder not staying in place - 10 years ago
If it's really the hot end - which sort of mount are you running? There are several variations. Assuming you are using a Wade's derivative extruder (and we aren't talking about the hot end): There are two bolts and nuts that pull the extruder down to the carriage. If the nuts have stripped out, you will either need to re-print the extruder base or shim them.by uncle_bob - General Mendel Topics