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People building or using RepRaps.
Re: Heatbed vs 3d printer size - 10 years ago
I have a 12"x12.5" bed with a 24V, 450 Watt heater. There is no effect on the controller- a standard, unmodified RAMPS board. I power the heater from a 24V transformer and switch power into the transformer using an SSR connected directly to the RAMPS board. The SSR doesn't even get warm, and the bed heats to 105C in about 7 minutes. I used to use a switching power supply but burned it up in sby the_digital_dentist - Mechanics
Re: Printer stops extruding PLA after about one minute, running out of options. - 10 years ago
Good!by the_digital_dentist - Mechanics
Re: Printer stops extruding PLA after about one minute, running out of options. - 10 years ago
Check the filament where it is pinched between the gear on the motor and the bearing. Is there a round divot cut into the filament? If so it indicates that the hot-end is jamming. Play with the temperature setting of the hot-end- don't trust the electronics to read the correct temperature unless you can verify it for yourself with a reliable thermometer- either a thermocouple or RTD. If you cby the_digital_dentist - Mechanics
Re: Bed leveling issues - 10 years ago
The bed leveling serves only one purpose: to get the first layer of your print to stick to the bed. The bed has to be level relative to the extruder nozzle at all points on the bed so that when the nozzle visits those places it will "press" the plastic onto the bed with equal pressure everywhere. That means you must move the extruder nozzle around the bed in order to check and level the bed. Aby the_digital_dentist - Mechanics
Re: SnakeBite Extruder - 10 years ago
I started out thinking of a design that used a single nut, then realized it would try to twist the filament, so then I thought about how to stop filament rotation (square filament?). I considered pizza cutter type wheels to dig into the filament and stop rotation, then came up with the idea of using a second nut turning in the opposite direction, then realized I'd need left hand threads, then, aby the_digital_dentist - Mechanics
Re: SnakeBite Extruder - 10 years ago
I think the retraction will be fast enough, but right now the problem is that uneven torque on the filament, caused by one nut hanging on tighter than the other, is causing the filament to rotate with the lower nut when the thing tries to retract. That prevents the molten filament from being sucked back into the nozzle and causes blebs in the surface of the print where the retracts are supposedby the_digital_dentist - Mechanics
Re: Long Linear Motion, Best Choice? - 11 years ago
Unless you want to print very slowly, and with very large prints that is going to take a loooong time, I'd suggest building the machine with architecture similar to the Makerbot machines. Moving a large, heavy print bed in the Z-axis is easier than moving it in the Y axis, though the mechanics are more complicated. My machine has a 12"x12.5" printbed and besides being large, the bed is heavy (1by the_digital_dentist - Mechanics
Re: SnakeBite Extruder - 11 years ago
Status update: further development is delayed by a nasty cold and even nastier income tax season. Those of you not living in the US should count yourselves lucky that you don't have the sort of crap we have to go through every year- there is no greater waste of time, effort, money, and most importantly, human intellect, than the US income tax preparation industry.by the_digital_dentist - Mechanics
Re: SnakeBite Extruder - 11 years ago
I did some thinking about what might be causing the loop blebs. I think it is occurring during retracts- i.e. the retraction isn't working as it should. I have clipped a spring clamp onto the filament entering the extruder to check rotation of the filament. What I have noticed is that the filament twists back and forth a few degrees as the machine prints, primarily due to misalignment of the nby the_digital_dentist - Mechanics
Re: SnakeBite Extruder - 11 years ago
I have been out of town for the last couple weeks, but I'm back and ready to start again... Quotecozmicray If one were to use a solid shaft (Brass, Al, Steel) with a hole drilled in it, What length of threads should be tapped into the shaft. Are the 3 or four threads of a nut optimum? I have no idea what is optimum. I started with off-the-shelf stuff to see if it would work at all. If you getby the_digital_dentist - Mechanics
Re: SnakeBite Extruder - 11 years ago
QuoteBill Clark those loops on the surface are strange. I'm wondering if the (scanned?) surface is just "dirty". The object was made by extracting soft tissue data from a CT scan. I have printed it before with no issues. The loops are definitely a problem related to the SnakeBiter or firmware settings or both.by the_digital_dentist - Mechanics
Re: SnakeBite Extruder - 11 years ago
The specs are all in the instructions page at thingiverse. These are the gears I used:by the_digital_dentist - Mechanics
Re: SnakeBite Extruder - 11 years ago
I spent most of yesterday experimenting with firmware and slicer settings to get good quality prints from the SnakeBite extruder. I'm getting closer- video of latest print here: This print took about 11 hours to complete. There are numerous small blebs in the surface, many of which were carried there from the support material, but some others that are loops that I don't know how to explain.by the_digital_dentist - Mechanics
Re: SnakeBite Extruder - 11 years ago
Compact and lighter will come later. I do have a slightly more compact version that uses 20 tooth gears on the nuts with a 30 tooth gear on the motor, and smaller bearings. That reduces size and should increase speed by about 50%. I'll be testing that later. Right now I have to figure out the firmware and slicing tweaks to get quality out of this one and test its speed limits.by the_digital_dentist - Mechanics
Re: Another Remote Extruder 
- 11 years ago
I think it can be made to work. Even if mechanical losses are high, you can use a bigger motor and more current to drive it. If you had to you could mount a set of bearings in the gear to reduce sliding friction along the square rod. It may not be necessary to make the square hole in the gear all that close fitting on the square rod. The whole carriage is going to be moving smoothly on the guby the_digital_dentist - Mechanics
SnakeBite Extruder - 11 years ago
I've been testing a new extruder design that uses counter-rotating nuts to drive 3mm filament into a Budaschnozzle clone hot-end. I was originally posting under this topic: "new light extruder concept". Summary: A simple differential gear arrangement drives two, 6-32 nuts in opposite directions. One nut is left hand threaded and the other is right hand threaded. The reason for using two nutsby the_digital_dentist - Mechanics
Re: SnakeBite extruder test #2 - 11 years ago
I'm going to start a new thread on this topic and stop posting in this one. Look for "SnakeBite Extruder" as the new thread topic.by the_digital_dentist - Mechanics
SnakeBite extruder test #2 - 11 years ago
I dialed the acceleration and jerk settings back and ran the same print again without reslicing, video here: Retraction is working properly, and the blobbing is gone, but it doesn't seem to be laying down enough plastic. There are gaps between lines in the bottom and top layer infills- this was true in the first test parts, too. I will recheck my steps/mm calibration for the extrusion and setby the_digital_dentist - Mechanics
Re: New light extruder concept out of bolt - 11 years ago
I repaired the Budaschnozzle and mounted the whole assembly on my printer. First test looks promising! I didn't see the motor reversing at all during this print even though retraction was turned on when I sliced the stl file. It is running at 100mm/sec. I'll tweak the motor current, reslice and make sure I have plenty of retraction turned on and try again, next time with a larger object that lby the_digital_dentist - Mechanics
Re: Timing belt gear with 10mm hole in it - 11 years ago
Makerbot is the name of a company, not any specific machine. What are you building? Gears and timing belts all have basic specs- The gear has to fit on a motor shaft or on a threaded rod. What is that shaft/rod's diameter? The gear will have a diameter or specific number of teeth. The gear will be made to accommodate a specific width of belt. The gear will be made for compatibility with a specby the_digital_dentist - Mechanics
Re: New light extruder concept out of bolt - 11 years ago
I attempted a print and discovered that my budget budaschnozzle copy was clogged. The threads on the aluminum extender tube got mangled when I took it apart to clean it out. I'm dead again until I get a replacement. Stay tuned! The nuts did chew into the filament when it was trying to push against the clog, but when I reversed it the filament backed out OK. The knob of melted filament that wby the_digital_dentist - Mechanics
Re: Timing belt gear with 10mm hole in it - 11 years ago
Are you asking for a source for a timing belt gear that fits on a 10mm shaft? Do you already have the belt or do you need a belt to match that timing gear also? If you have the belt you need to specify the type and size of belt- all timing gears are not the same. Are you making a really big machine? A 10mm shaft would be on a huge motor- much larger than typically found in a 3D printer. Thby the_digital_dentist - Mechanics
Now called SnakeBite extruder - 11 years ago
Getting closer! I did another redesign to reduce size a bit, printed the parts, tested operation pushing filament back and forth, bolted to a mounting plate with a Budaschnozzle hot-end, uploaded files to thingiverse and video to vimeo and put blog post at the Milwaukee Makerspace site. I will be printing with it tonight or tomorrow and will make video of success or failure for all to enjoy. Vby the_digital_dentist - Mechanics
Re: New light extruder concept out of bolt - 11 years ago
If the filament breaks inside the nut, you could chase it out with a small drill or even a tap pretty easily. I can't think of anything that would cause the filament to break inside the extruder. If one side were turning and not the other you could develop some pretty big force on the filament, but if that happens, you have bigger problems anyway since both nuts are driven by gears. I suspectby the_digital_dentist - Mechanics
Re: Use pulley as idler - 11 years ago
I have been using bearings as X and Y axis idlers in my printer for about a year. I recently put half twists in the belts and found it does make a small difference in print quality, at least with the type of belt I am using. I am using a 5mm pitch urethane belt with embedded steel cables. Before I twisted the belts, when I printed an object with straight sides running parallel to the X or Y axby the_digital_dentist - Mechanics
Re: New light extruder concept out of bolt - 11 years ago
Nut problems! The drill size I started with doesn't seem to work right. When I file the tapped hole larger to bite the filament less, the force required to spin the nut doesn't drop until it suddenly drops too much and the filament starts slipping. I think the nuts are going to have to be made by tapping a small collet so the final diameter can be adjusted. I'm going to fall back to the origiby the_digital_dentist - Mechanics
Re: New light extruder concept out of bolt - 11 years ago
I think the ideal pitch is one that results in a whole number of steps per mm of extruded filament, but that will also depend on the gears you use. I have 30 and 20 tooth gears and I used a 32 tpi taps to make the nuts because they were cheap, readily available, and about the right diameter. With these gears, one rev of the motor will turn the small gear 1.5 times, which will move 1.19mm of filby the_digital_dentist - Mechanics
Re: New light extruder concept out of bolt - 11 years ago
I finished fabricating the nuts and assembled everything today. Test printing will commence tomorrow if everything works. There are more photos of the assembly here: Extruder cover assembly Extruder side view Extruder assembled The small gears, tubes, drive nuts, and bearings all come off the unit by removing the four cover screws, without taking the extruder off the printer mounting plate.by the_digital_dentist - Mechanics
Re: New light extruder concept out of bolt - 11 years ago
While waiting for some parts to arrive I decided to address some of the less desirable features of the extruder. - using smaller gears to turn the nuts to reduce overall size and speed up extrusion (let's hope the motor has sufficient torque for the extra load) - using smaller bearings to shrink the size (went from 5x16x5mm to 5x8x2.5mm) The previous iteration size, excluding motor, was 100mmby the_digital_dentist - Mechanics
Re: New light extruder concept out of bolt - 11 years ago
Check out DesignSpark Mechanical- free CAD, similar to Solidworks. http://www.designspark.com/eng/page/mechanical You don't have to make the gears. If you make/print them you have to worry about strength as well as some means to affix them to the tubes/shaft. The gears I used, which can press fit onto a 5mm shaft/tube, are available on ebay or from American Science and Surplus very cheaply.by the_digital_dentist - Mechanics