> Endstops are 1 per axis for zero positioning. It was originally designed for more, but last I heard there aren't enough pins on the processor to properly use them all. There are enough pins, even on a standard Arduino, for a standard RepRap. You only have one extra pin, so if you want to add something else, like a heated bed or extruder encoder you will have to cannibalize the max sensors.by mccoyn - Reprappers
> To reduce cost for first time 3D printer fans, I am also looking at making a single controller board for the whole machine This sounds a lot like a project I have been working on. It will by a 4" x 3" PCB with all through hole mounted hardware. The main components will be 4 Pololu stepper drivers, an Arduino Mini and a couple MOSFETs. Here is my cost breakdown: stepper drivers: 4 x $13by mccoyn - General
2A for a 6 Ohm heater running at 12 V.by mccoyn - Plastic Extruder Working Group
Thanks. I was thinking about doing it, or asking someone else I know to do it, but I didn't want to hassle with international shipping.by mccoyn - Wanted
Since this board is smaller, will there be problems with keeping the chip cool? How many amps can it handle before overheating?by mccoyn - For Sale
Having nice small steps for the z-axis is very helpful as you can set the layer thickness precisely. So a threaded rod drive there is a good idea.by mccoyn - General
I've been thinking about putting a force gauge between the thermal barrier and the extruder drive block. In normal operation, this would measure the pressure in the extruder chamber allowing the firmware to estimate the flowrate and adjust the feedrate to match. I was thinking it could be used to home the z-axis as well and it should be able to map the bed as you suggest.by mccoyn - General
It can be simpler than that. Take the previous layer's perimeters and offset them by the layer thickness and then take the intersection of that shape with the shape made by the perimeters of the current layer and you get the new perimeters for the current layer that don't violate the 45 degree rule. The disadvantage, as Wade was alluding to, is that you no longer can span 90 degree overhangs anby mccoyn - General
The 2.3 version has a safety thermal shutdown which will prevent the chip from damaging itself. I ruined one 1.2 board before I learned that the standard heatsink was not enough.by mccoyn - Controllers
> When I hit extrude in the Host the stepper driver lights go out meaning the enable pin unlocked the coils That seems odd. They should be on and begin flashing when you hit extrude in the host. I'm not exactly sure how the enable signal is managed, but it might be backwards in your setup. Try connecting the enable signal to ground or +5V and see if you can get it working. I believe the Sby mccoyn - Reprappers
> My question, is the drive speed maximized in belt driven systems? Only a few people have pushed the belt drive to its limits. On my Darwin system, the speed is limited by the extrusion rate, with lots of head room on the xy feedrate. When I try to increase speed, I have trouble maintaining temperature.by mccoyn - General
I've had the same issue with my wood Darwin. The primary cause was that the drive rod and the motor shaft were not aligned well. Wanting to save on time, I bought an expensive shaft coupler that could handle the problem. I still have an issue with the bed constraint brackets which have too much play. I'm planning to print replacements to those which are more accurate. I thought I was the onlby mccoyn - General
If someone has printed a complete Mendel on a McWire it would be very useful to get that person's Skeinforge or RepRap Host preferences and add it to the Wiki.by mccoyn - Administration, Announcements, Policy
I use engine oil. I believe anything that won't smoke at the temperatures you are working at will work.by mccoyn - Plastic Extruder Working Group
> My impression is that most people's extruders work well and ours does not. I think most people spend a lot of time trying to get their extruders working well. I've printed about 150 parts on mine and I'm still having trouble with the thing. ABS seems to work a lot easier than PLA. I've seen PLA leak through threads where ABS has not, so I think PLA is a more mobile in tight spaces and thby mccoyn - Plastic Extruder Working Group
In the firmware, in extruder.cpp, there is a variable called high_heat, which gets set to 255, I believe. If you decrease this number you will decrease the maximum PWM duty cycle, which will slow down the heater and give you the desired results. When I had a 4 Ohm heater I had to turn this down to 200. I also had to reduce the low_heat variable because it would always heat to 180 C when I turnby mccoyn - Plastic Extruder Working Group
In my experience, the cost of labor dwarfs any other costs of making stuff with a RepRap. You can't just say "if your machine is reliable enough" because no one has managed to make a super reliable machine without investing hundreds of hours of their own time learning about RepRaps and making lots of adjustments to a machine to make it reliable. You then have to account for that upfront labor cby mccoyn - General
I made ABS paste by dissolving some scrap rafts in acetone. It doesn't cure quickly, but it makes a pure ABS bond. I've been wondering if this can be used as an epoxy for joining the thermal barrier to the extruder block.by mccoyn - General
When I attempted to print a driven-pulley with 0.3 mm layers and a 0.5 mm nozzle it did not work. The material didn't stick well enough on the perimeter to be stretched around the fine details. I ended up with a cylinder, not a pulley. When I printed with 0.45 mm layers (and 0.54 mm thread width) it worked much better. I tried this in both PLA and ABS.by mccoyn - General
I am not using capacitors on my thermistor setup. It works fine. The firmware does an average of three readings anyways. See the attached image for my thermistor "board".by mccoyn - Controllers
Has anyone tried printing thicker layers on a McWire to speed things up? It seems like switching from 0.5 mm to 1 mm layers you could print stuff in a quarter of the time. Sure, you lose accuracy and the texture of the parts is a lot more noticeable, but with some finish drilling the parts should be serviceable. You might have to slow things down for some specific parts, like the pulleys. I'vby mccoyn - General
Spacexula, I think the answer to your question comes down to how reliable your system is. I printed a set of parts to build a Mendel on my Darwin and tried to build up the Mendel myself while printing over stuff off on my Darwin. Unfortunately the Darwin wasn't quite as reliable as I needed it to be and I didn't spend much time on the Mendel. For me, it made more sense to give the parts to soby mccoyn - General
Nelson, You should start a new topic with this question. I think you will get more responses that way.by mccoyn - General
Forest, Have you released your rack and pinion script yet? I'd like to see if I can print it and show off the parts to some people I'll see this weekend.by mccoyn - General
Maybe your threads aren't very good. You can run a threading die over it to recut them. It'll take a lot of work if you do it by hand.by mccoyn - General
The v1.2 stepper boards will work fine with the generation 3 electronics. The newer boards use a different chip that requires fewer external components, does not waste as much heat and has a temperature shut down sensor so you don't damage the chip. Both boards are controlled by the same step/dir/enable signals.by mccoyn - Reprappers
I have a working RepRap and I'd be willing to send you something to be assembled at that show. Send me a PM if you decide to do it.by mccoyn - General
The debugging stuff is set to STDOUT. If you are using Ubuntu then selecting Run in terminal will let you see this. I'm not sure where this stuff ends up in Windows. What OS are you using? How are you launching the RepRap host?by mccoyn - Controllers
I made a wood block one as well. Mine is larger and doesn't have the short shoulders (which I believe are there to allow you to use smaller screws.) I don't have the dimensions anymore, I looked at the design, figured out how it works and laid out something that was easy to build.by mccoyn - Plastic Extruder Working Group
I loosened some of the screws that hold the bed in place so that the rods have a little freedom to move relative to each other. I kept all the screws on the corner with the motor tight as well as those on the opposite corner.by mccoyn - General