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Designs that do not fit in other categories. Previously named "New RepStraps and Post Mendel"
Re: Valved Bowden - 3 days ago
How does it add control?by the_digital_dentist - Plastic Extruder Working Group
Re: Valved Bowden - 4 days ago
If they are both extruding the exact same amount, the small one can't add/subtract from the extrusion. The only benefit will be that the already minimal force required to pull the filament from the spool will be reduced by the remote extruder. What is the problem you're trying to solve and how does this scheme solve it?by the_digital_dentist - Plastic Extruder Working Group
Re: Valved Bowden - 4 days ago
I'm trying to imagine how this would work. Maybe put a slightly larger drive gear on the remote extruder (or set a smaller steps/mm) so that it is always trying to push or pull a little more than the smaller direct extruder, but... there is limited space inside the tube for the filament. On a long extrusion without retraction the filament will "fill" the available space as the smaller extruder rby the_digital_dentist - Plastic Extruder Working Group
Re: E3D Hemera Direct Kit or Bowden V6 for Sapphire Plus? - 5 days ago
If you want to print flexible filament, Bowden is out.by the_digital_dentist - CoreXY Machines
Re: Loosing reference after any layers - 8 days ago
I think it's more likely the driver chips overheating, especially if the controller has those crappy little modules that can't dissipate any heat. If the cable went intermittent, it would probably destroy the driver very quickly. Do you have steel core belts on the XY mechanism?by the_digital_dentist - Printing
Re: x-axis supports: - 9 days ago
In SoM I used an aluminum tube to mount the X axis guide rail. On the guide rail side of the tube I drilled holes to fit the screws that would hold it down. On the back side of the tube I drilled larger holes that would allow a nut driver to be inserted. Don't try to put the mounting screws all the way through the tube with the nuts on the back side of the tube. That will only crush the tube whenby the_digital_dentist - CoreXY Machines
Re: Loosing reference after any layers - 9 days ago
The shifting appears to be at a 45/135 degree angle. A corexy mechanism moves that way when one motor is not turning and the other is. I'd inspect motor cables and connectors and make sure the motor driver chips aren't overheating.by the_digital_dentist - Printing
Re: What is practical limit of layer shifting at all? - 13 days ago
Flat vertical walls are a particular problem, even in single walled vases because plastic shrinkage easily distorts the shape and causes the straight wall to "potato chip". Curved walls usually suffer less of that problem.by the_digital_dentist - General
Re: Steps/ mm calculator. - 14 days ago
20 mm is too small to calibrate your axes (unless your printer has a 25 x 25 mm bed). A 20 mm cube prints so fast that the print quality degrades as the print builds up because you're dumping hot plastic on top of hot plastic. Where do you measure it to decide if it's 20 mm on a side? Print the largest object you can accurately measure and use it to calibrate. A large object will print with betteby the_digital_dentist - General
Re: What is practical limit of layer shifting at all? - 14 days ago
If your printer is made well- low or no backlash in the mechanism and the Z axis works without wobble- when you print a single walled vase you'll see the layers stacking up perfectly. As soon as you change to multiple walls, the problems start. As Mr. Clark says, the rough vertical walls are a problem of extrusion, geometry, properties of the plastic (shrinkage, etc.) etc., not necessarily a prinby the_digital_dentist - General
Re: Top surface pattern - 15 days ago
Yes, that's typical. Try printing in thinner layers...by the_digital_dentist - Printing
Re: x-axis supports: - 16 days ago
Have you considered tool changing instead of a dual extruder? A simple aluminum tube is lighter and more rigid than the same size t-slot.by the_digital_dentist - CoreXY Machines
Re: Bed heating power - why don't they get to temperature quicker. - 20 days ago
QuoteMCcarman 24v bed is no better as they are typically 2 x 12v circuits so it doubles the resistance as well as the voltage. If you push the voltage up at the cold start you draw more current at the start and risk the electonics. What you actually want is to increase the current as the bed heats. 24V is better if you're trying to heat the bed, because it will use 1/2 the current that a 12V heaby the_digital_dentist - Tech-Talk
Re: Core XY belt paths - 20 days ago
It looks like you've taken the twisting torque from the extruder carriage, converted it to two unequal torques, and moved it to the bearing/pulley blocks at the ends of the X axis. I've seen different belt arrangements that claim to eliminate this or that torque, but in the end does the torque they're trying to eliminate somehow affect the print? Unless the X axis is twisty and/or there is play iby the_digital_dentist - CoreXY Machines
Re: Question regarding CoreXY design (in particular the_digital_dentist's UMMD) - 21 days ago
Some t-slot has a sort of flat surface and some doesn't. The stuff I used didn't, so I milled flat surfaces into the vertical t-slot members that the Z axis guides rails mounted on. You can see the shallow "slot" I milled at the very top of this picture: IRIC, the "slot" was 0.25 mm deep. The frame of the printer is built square by milling the ends of the t-slot and matching lengths of the fby the_digital_dentist - CoreXY Machines
Re: Bad Nema 17 stepper motor? - 21 days ago
Stepper motors almost never fail. All they are is fixed coils of wire and magnets on a spinning rotor. After a LOT of use, the bearings may fail depending on how the motor is loaded, but it's really hard to burn up the coils. If you do burn up the coils, you will be able to smell it. No smell, no burned coils. I had an industrial surplus stepper fail after several years in a 3D printer (plus Godby the_digital_dentist - Printing
Re: Question regarding CoreXY design (in particular the_digital_dentist's UMMD) - 22 days ago
Yes, two linear guides for the Z axis. No, no alignment or thermal problems. The linear guides are bolted to t-slot that is bolted to the printer's frame. There is a t-slot cross bar at the bottom and the bed support is also a t-slot that runs across the two Z guides. I was concerned that with the chamber being heated that there could be some problems if the whole frame didn't heat up as a unit,by the_digital_dentist - CoreXY Machines
Re: Bed heating power - why don't they get to temperature quicker. - 27 days ago
You're asking your printer to do something it was never intended to do. I know the marketing BS said the printer was "ABS compatible", but if you were trying to sell 3D printers, you'd have to say that too, even if it wasn't true. There's physics: And there's power input... Unless the bed is very small, 12V power is a lousy way to heat a bed. Most 12V bed heaters are underpowered for the sizby the_digital_dentist - Tech-Talk
Re: Nozzle repeatedly clogging while printing Ninjaflex TPU 
- 4 weeks ago
Ooops. The upper end of the temperature range.by the_digital_dentist - Printing
Re: Nozzle repeatedly clogging while printing Ninjaflex TPU - 4 weeks ago
Reduce the drive gear pressure for flexible filaments and try printing in relatively thick layers. print slowly- maybe 30-40 mm/sec. If you have a 0.4 mm nozzle, print in 0.25 or 0.3 mm layers. Print at the upper end of the recommended range for the filament, too.by the_digital_dentist - Printing
Re: Why you should power off when unattended - 5 weeks ago
I think those modules are poorly engineered. They can't dissipate enough heat because of the small size of the circuit board. You can get better controllers that don't use modular motor drivers...by the_digital_dentist - Safety & Best Practices
Re: Core XY build - feedback appreciated - 6 weeks ago
Should be fine, then! I use a Bridgeport mill at the Milwaukee Makerspace. I recently acquired a three flute, 1/2", tungsten carbide end mill with a 50mm cutting length, specifically for milling t-slot. It leaves an almost mirror finish on the ends of the t-slot!by the_digital_dentist - CoreXY Machines
Re: Core XY build - feedback appreciated - 6 weeks ago
With the XY stage built on a plate mounted on top of the verticals, and another plate on the bottom, the lengths of the verticals better be well matched or the XY stage is liable to twist.by the_digital_dentist - CoreXY Machines
Re: Heatsink pastes for hotends - 6 weeks ago
More likely the Dunning-Kruger effect than politics...by the_digital_dentist - General
Re: Heatsink pastes for hotends - 6 weeks ago
Far too much. I will remain firmly rooted in reality.by the_digital_dentist - General
Re: Heatsink pastes for hotends - 6 weeks ago
QuoteleadinglightsWhile I am not unconcerned about the possibility of failure, this is only because of the very small size of the resistors I am using, not because there is any problem with the materials or the construction of wirewound resistors which render them unsuitable for this purpose. I would also not expect a 3D printer manufacturer to use them, but this is because variables that do notby the_digital_dentist - General
Re: Core XY build - feedback appreciated - 6 weeks ago
It looks nicely built, except I agree with prototypical- standing the pulleys on posts is not a great way to go. We'll see how the cantilevered bed behaves when the X axis is flying back and forth on the Y axis rails. They have a tendency to bounce, but if the construction is solid enough, it may not be an issue. Where will you be mounting the electronics?by the_digital_dentist - CoreXY Machines
Re: Heatsink pastes for hotends - 6 weeks ago
There's a huge difference between building a printer and buying a stratasys printer. You can get 99% of the stratasys function/performance for 5% of the cost with a DIY, and learn useful stuff along the way. But a resistor vs a heater cartridge? You might save a few pennies after spending many hours screwing around with it, but will you be able to trust it to work for any length of time? There iby the_digital_dentist - General
Re: X axis wobble in corexy printer - 6 weeks ago
The tension in one belt affects the tension in the other, so I think the plot represents the sum of the varying tensions in both belts. I'm not sure you can imply anything about the relative phases of the out of round positions of the pulleys or even the relative magnitudes of the out of roundness based on the plot. The idlers are all stacked bearings and the diameter is 22 mm. If one of thoseby the_digital_dentist - CoreXY Machines
Re: Heatsink pastes for hotends - 6 weeks ago
Actual heaters that are designed to transfer the heat to whatever they're mounted on cost about $5. You can even specify power and voltages. Why mess around with resistors that are not designed for the purpose?by the_digital_dentist - General