Timing is the issue. You want to start one segment as soon as the previous one is done. Otherwise, plastic will ooze out of the nozzle and make a mess. I'm not entirely sure what features that stepper board has available. If you can queue up a few moves so you aren't running at the whims of the OS thread scheduler it could work.by mccoyn - General
I believe Mendel is still under development. Especially when it comes to documentation. If you want a fully worked solution with complete documentation you might want to look at the Darwin design.by mccoyn - Reprappers
I do the same thing. I output 0 to turn the PS on and set the pin to input to turn the PS off. I don't have the Arduino powered by the PS standby so if I unplug the USB cable or the computer's power cord, the power supply turns on, which kind of sucks. When I put a volt meter on the green wire, it reads 1.5 V, I think. So outputting a digital 1 (5 V) wouldn't be very nice.by mccoyn - Controllers
This was discussed a while back and multiplexing based on direction was brought up. The conclusion was, yes, there are a few clever ways to save pins on the endstops, but just removing the max stops works as well and is simpler. I haven't kept my max stops properly aligned and functioning well because I never hit them and I have bigger problems to solve.by mccoyn - Controllers
I have recently found that stretching to achieve better z resolution also makes it harder to print fine details in x and y since the filament gets pulled inside curves.by mccoyn - General
I wonder if there is a problem with trying to make the full cut in one turn. If you tapered the end and then tapped it again, it might not wear the threads down as much. Or, you can try and find a pre-made threaded tapered cutting thing that is designed to be driven.by mccoyn - General
I've been following the RepRap community for a while. All of the issues that maitri982 brought up have been considered, but none of them have received enough actual experimentation time to be resolved. Many people who are eager to work on them don't have fully functioning machines to work on. So, I tend to believe these issues will be worked out by 100 people trying lots of different ideas inby mccoyn - General
I generally prefer the BSD license over the GPL as well. Why does open source need to be at war with commercialism? I prefer to build something that can benefit as many people as possible, regardless of whether those people happen to share my philosophical views. That said, I'm happy playing within the community under the GPL if that is what is generally preferred. I am strongly against requiby mccoyn - Administration, Announcements, Policy
You want to avoid hot spots because these will cause your plastic to burn or force you to work at a lower temperature for the cold spots. Having a brass barrel with the wire outside works very good at distributing the heat so the whole thing is close to the same temperature.by mccoyn - Plastic Extruder Working Group
If you have a layer of aluminum below a layer of steel, the difference in conductivity will help to spread the heat out (it is easier for heat to move along the aluminum than straight out the steel). You need a better insulator below the aluminum otherwise you will lose all your heat that way. This is all rather complicated since it appears that a simple sheet of aluminum heated from the bottomby mccoyn - General
I have to agree with nophead. Calculating for my extruder, 200/steps per revolution with 20 mm circumfrence gives gives .1 mm/step feeding into the heater, but that gets reduced from 3 mm to .33 mm diameter, meaning I get about 10 mm of thread per step of the extruder motor. With my feedrate of .1 mm/step I'm taking 100 feed steps for each flow step. This seems way out of whack. Yet I don't sby mccoyn - Reprappers
We already have steel rods providing most of the bulk-material for the Mendel. When I think about any of the existing pieces, like the frame-vertex I can't see how they could be made out of LEGOs. The two holes for the 60 degree angle come very close on one side and so you might as well make them out of one piece. Then you have to two perpendicular pieces in the gap, and the LEGO pieces for thby mccoyn - General
I feel better about mounting my motor holder and leadscrew-base upside down now!by mccoyn - For Sale
I think you have to send an email to BayArea@makerfaire.com, which will get you on the mailing list and then tomorrow there will be information sent to that list that explains how to sign up. Let me know how it goes because I am trying to do the same thing for the Detroit Maker Faire.by mccoyn - General
> Yes I get great results and have blogged the power required, etc, See all my posts since the start of the year. Oh sorry about that. I haven't been keeping up with the blogs in the last few weeks. It should be worth the read.by mccoyn - General
I built a heated bed some time ago and I never blogged about it because I didn't consider it much of a success. I had no idea how much heat would be required to heat my 150x75 mm aluminum plate. I initially started with two 10 Ohm lengths of nichrome wire in parallel held in place on the bottom of the plate and powered by 12 volts. This results in about 30 W, which clearly wasn't enough. Nextby mccoyn - General
I haven't run into anything that Skeinforge takes hours to process. In general the Skeinforge time is always a lot less than the printing time. I have a 3.06 GHz P4. I think the architecture of Skeinforge needs to change a little to allow simultaneous printing. I believe each phase starts at the first layer and goes through all of them and then the next phase runs starting at the first layerby mccoyn - General
I think a RepRap conference is a great idea and doing it virtual might be fun. I think we should still have regional meetings at hackerspaces and such so that we get the food/social stuff going on, but they can all be connected by a video feed. Also having meetings means the people presenting have some people to talk to and interact with. I really think we should have live video between the coby mccoyn - General
All the computer does is stream commands to the machine. They could easily be stored on an SD card. That is a few hundred dollars cheaper than buying a netbook or phone.by mccoyn - General
There is an interesting discussion about using acetone to finish ABS. It gives it a glossy finish. It may be that with the right mixture of acetone and ABS you can make the layering effect disappear. Perhaps with a few coats. As for changing the Z resolution it is straight forward. You can set that value in Skeinforge to whatever you want and then you have to decrease the flow rate so youby mccoyn - Plastic Extruder Working Group
I uses a stepper, but davidbuzz has created a fork from it which appears to support DC motors.by mccoyn - RepRap Host
I'll merge it when I get some time. Right now most my time is spent on hardware issues.by mccoyn - RepRap Host
The Mega was pretty simple, but the ATMega328 had a bug which had to be fixed.by mccoyn - RepRap Host
Those numbers look correct. You might want to check to make sure it is the z axis moving the wrong amount and not that the layers are too thick. This is easily accomplished by homing and then moving 50 mm and the measuring the distance from the extruder head. I had a problem for a while with my layers being twice as high as I expected. This occurred because there was backlash in my y axis. Wby mccoyn - RepRap Host
I've modified the 5D firmware so that it will work on an Arduino Duemilanove w/ ATMega328P. To help anyone using a similar board, I've uploaded my firmware to github. I merged my changes with joaz's changes so this will also support Arduino Mega.by mccoyn - RepRap Host
The McWire is slower and more accurate than the RepRap designs. The McWire uses a threaded rod to drive the x and y axis, and so it moves around 1 or 2 mm per revolution. The RepRaps use a belt drive for the x and y axis and so they move around 40 mm per revolution. Generally speed is more important for additive processes than subtractive processes because the amount of work you have to do is pby mccoyn - General
Darwin is 40 mm per revolution for the x and y steppers and 1.25 mm per revolution for z.by mccoyn - Reprappers
240 C seems to work well. If you have white ABS then you know you've gone too hot if you see it start to come out with a yellow tint. Other than that, the hotter the better.by mccoyn - General
I just spent an hour trying to get one of these files to work. Could someone check the corrected files into sourceforge? I downloaded them here.by mccoyn - Reprappers
The old Arduinos used the ATMega168P. I think, I know the number was 168, but I'm not sure if the P was there. Judging by the list of chips on the Atmel site I believe there is only one ATMega328, and it is P.by mccoyn - RepRap Host