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People building or using RepRaps.
Re: VENT YOUR PRINTER! DO IT NOW! - 1 year ago
Well, I guess if 55-60 million people die every year we shouldn't bother trying to prevent any deaths, by any cause, because people will just go out and find some other way to die anyway. K-12 defibrillators- maybe those aren't there primarily for the kids, maybe they're there for the adults that use the space as well, you know, teachers, parents, grandparents, staff, etc. I've had several COVIby the_digital_dentist - General
Re: VENT YOUR PRINTER! DO IT NOW! - 1 year ago
Yikes! Feel better soon! My eye would have been the 2nd last place I would have touched!by the_digital_dentist - General
Re: Problems with black PLA - 1 year ago
try higher temperature...by the_digital_dentist - Printing
Re: CoreXY Design Alternative - 1 year ago
I think linear motors are unlikely to be used in 3D printers, at least by hobbyists, any time soon. They are just too expensive to justify the increased cost over the existing cheap solutions. As far as using t-slot as a cross bar goes, 20mm square tubing will be more rigid. Rectangular tubing of the same size will be more rigid than any same-sized t-slot. T-slot is not rigid stuff.by the_digital_dentist - Mechanics
Re: Custom Firmware Build - 1 year ago
RepRap Firmware that runs on Duet boards can accommodate different mechanical behaviors. You have to define the motion mathematically and then make some changes to the firmware to use the new definition that you created. You should search and ask about this on the Duet forums. M669 is used to select/define kinematicsby the_digital_dentist - General
Re: Weird problem - 1 year ago
Did you preview the gcode before trying to print? Does it look the way it should at the place where the print is failing? Try turning on "detect thin walls" in the print settings. If that doesn't work, I'd try reverting to the latest stable release and see if it has the same problem.by the_digital_dentist - Printing
Re: core xy layers not aligned - 1 year ago
Pix of the printer? The only way it could be a z axis problem is if the Z axis guide rails are not perpendicular to the XY plane defined by those axes' guide rails.by the_digital_dentist - Printing
Re: core xy layers not aligned - 1 year ago
Along which direction is the shift occurring? X, Y, 45 degrees? Check that the drive pulleys are tight on the motor shafts. Some photos of the printer might help.by the_digital_dentist - Printing
Re: PTFE fumes: poor assembly order for E3D-v6 hot end? - 1 year ago
Sometimes it's just not worth the time and intellectual effort to try to make a silk purse out of a sow's ear. For about $15 you can get a good, all-metal hotend and not have to be concerned about PTFE fumes. I've been using one of these in UMMD for 3 years with no problems other than replacing the crappy fan with a good sunon fan for an additional $8 or so. It has several advantages over the E3Dby the_digital_dentist - General
Re: CoreXY Design Alternative - 1 year ago
20x20 t-slot for a 1m cube printer? No..... Being a mechanical engineer, you surely understand that as cross section goes up, rigidity increases dramatically. 20x20 t-slot is barely suitable for a 200x200 mm printer (nevermind that many larger hobbyist offerings use the stuff). You probably also know that a plain tube that's 20x20 is going to be far more rigid (and probably lighter weight, depenby the_digital_dentist - Mechanics
Re: CoreXY Design Alternative - 1 year ago
I don't think corexy is particularly complicated, and there's no "careful and tedious balancing" of belt tensions. Absolute belt tension isn't any more critical than in any other belt driven mechanism. The goal in setting the relative belt tensions isn't matching the two. The goal is to get the X axis square with the Y axis. The last time I did it, it might have taken 15 seconds. You thought balaby the_digital_dentist - Mechanics
Re: A functional PET-G waste paper bin printed in under 2 hrs - 1 year ago
Interesting filament. Am I seeing bubbles or is that some special additive in the filament to make it look that way? Is that a mix of different filaments or is the color shift a property of a single filament?by the_digital_dentist - Look what I made!
Re: How can you do 3D printing without a traditional nozzle - 1 year ago
Interesting. I wonder what the temperature gradient is across the teflon tube inside the heater block. It might be getting close to the decomposition temperature of the teflon. What was the print speed? It looked pretty slow in the video. I imagine it takes quite a bit of time to melt the filament through the teflon tube. At 1.75 mm line width and probably1 mm layer height, even if it goes slowby the_digital_dentist - Mechanics
Re: Rebuild worn CoreXY, what options should I consider? - 1 year ago
When you're buying linear guides via ebay, look for quality brands Thomson, THK, IKO, Bosch, etc. I avoid parts with "MGN" or "MGH" part numbers- the Taiwanese company (HIWIN) that started (?) that numbering scheme makes quality guides, but the vast majority are cheap knock-offs. Don't worry about the exact length of the rails- you can cut them down using a cutoff wheel on a grinder. Make sure yoby the_digital_dentist - CoreXY Machines
Re: 32-bit linux printer host software - 1 year ago
I wish you continued luck with it.by the_digital_dentist - General
Re: Rebuild worn CoreXY, what options should I consider? - 1 year ago
In the sand table I used printed flanges to help keep the belts on the pulleys over the very large size of the table. The printed tires on the bearings were used to push the flanges outward against the bearing flanges. I don't think you need either the wider flanges or the printed tires for a 300x300 mm bed printer. I needed them in the sand table because of its large dimensions. In UMMD doesn'tby the_digital_dentist - CoreXY Machines
Re: Rebuild worn CoreXY, what options should I consider? - 1 year ago
After I built my first printer, MegaMax, I kept a running list of all the problems I ran into as I used it. One of the things I wanted to do was to print ABS, but at the time I built the printer, I didn't know I would need a warm enclosure for the machine. So armed with the list of all the problems, I started making a list of changes that would address all those problems. When I was done I starteby the_digital_dentist - CoreXY Machines
Re: A new, smaller sand table mechanism: Arrakis - 1 year ago
No, I would not recommend using the type of bearings I used in the sand table for most 3D printing applications. There is too much slop. Sand tables are very forgiving of slop (except for the noise it produces). Most 3D printers need everything to fit tightly so they can produce accurate shapes and precise positioning of the lines of plastic on each layer. OTOH, if you're building a printer thatby the_digital_dentist - CoreXY Machines
Re: 3D printed sand table mechanism - 1 year ago
There are about a 1000 different things that you could do with this sort of mechanism- pen plotting, painting with an airbrush, light painting, you could use plaster powder instead of baking soda and mist it with water when the pattern finishes to harden it (or spray cyanoacrylate on baking soda for the same effect). I specifically avoided flashing lights or color cycling because I wanted the drby the_digital_dentist - Look what I made!
Re: A new, smaller sand table mechanism: Arrakis - 1 year ago
Blog post on Arrakis is here.by the_digital_dentist - CoreXY Machines
Re: 3D printed sand table mechanism - 1 year ago
Update: Similar edge motion reduction that I had programmed in Perl is now baked into Sandify and it works better than the Perl program I wrote. After running Arrakis at different speeds, I have found that lower speeds generally preserve pattern details better than higher speeds, so for very detailed patterns, I started setting the speed as low as 100-200 mm/sec. Drawing speed is specified in cuby the_digital_dentist - Look what I made!
Re: How to judge quality of printed PLA LM8UU/LM6UU bushings? - 1 year ago
And one day you'll take the printer to a friend's house and stop for coffee or lunch on the way leaving the printer in the car in the sun and that will be the end of your printer. Why would you use PLA for this instead of some other plastic? PLA is completely awful for anything that you want to last, especially anything that includes sources of heat such as a hot end, bed heater, and stepper mby the_digital_dentist - General
Re: 32-bit linux printer host software - 1 year ago
@4ndy you wouldn't be wasting a perfectly good circuit board, you'd be freeing it up for another project that needs stepper motor drivers and a gcode interpreter. Maybe something like this: If you search through posts here from several years ago, there were a LOT of problems with sending gcode via USB to printer controller boards. Printers would stop and stutter while a print was running becby the_digital_dentist - General
Re: 32-bit linux printer host software - 1 year ago
As my rustic grandmother in Tennessee used to say, "you can't make a silk purse out of a sow's ear".by the_digital_dentist - General
Re: Building a Mendel in 2021. What would you choose? - 1 year ago
Twists in the belts are only needed if the pulleys are small or you want quiet operation at very high speeds. The stacked F625s used in that design are still a little small to have the belt teeth hitting them- they could cause print quality problems (as well as making zipping noise at high speed). Gates recommends a minimum of 9 teeth in contact with a smooth pulley surface, and since the belts aby the_digital_dentist - General
Re: Building a Mendel in 2021. What would you choose? - 1 year ago
Flanged bearings are used because the toothless pulleys sold for 3D printers have bearings that are too tiny and will wear out very quickly. Flanged bearings are better because the balls in the bearings are much larger and should last a lot longer. This is the kind of small stuff that you don't have to learn by doing - you can rely on other peoples' experience and save yourself a lot of trouble,by the_digital_dentist - General
Re: Building a Mendel in 2021. What would you choose? - 1 year ago
It's great that you're going to try to design your own machine, even if it is based on someone else's design. One of your goals was to learn from the process, and you will most certainly do that. I can make a couple recommendations regarding that design. It appears to use a stacked belt corexy mechanism. Notice that right at the motors the belts bend 90 degrees and at the opposite corners the bby the_digital_dentist - General
Re: Spring steel sheet - 1 year ago
I print largish PETG items on PEI all the time. I use 70C bed. The prints stick, but come off easily enough by applying a few drops of IPA to the bed/print interface prior to prying them up. I use this type of tool to do the print release: I never liked either glass or hairspray...by the_digital_dentist - General
Re: Filament availability in the foreseeable future? - 1 year ago
I don't think there's any danger of resin printing replacing FDM for most people. 3D printing hobbyists are among the cheapest people on the planet. Resin printing is expensive, very messy, and stinky. As you scale it up in size, the expense and mess increase exponentially. Most people won't want to bother with it. There are plenty of plastic makers outside of China. OTOH, in the US I'd worryby the_digital_dentist - General
Re: Building a Mendel in 2021. What would you choose? - 1 year ago
A machine that moves the bed in Y will not scale up beyond about 300x300 mm. As the bed gets larger it becomes heavier and harder to throw back and forth at print speed. Deltas don't scale up well, either, so stick with a square/cartesian machine of some sort. I suggest that instead of one of the old bed flinger designs, you start with a design that will scale well such as a core XY in which theby the_digital_dentist - General