Hard to say exactly from that photo, but my first guess would be not enough plastic - you should see nice exact filaments everywhere, not a loose mess. Check to see if your extruder is slipping, and check your X axis for slipping or missed steps as well. Make sure the E value in the is appropriate for your stepper, gear ratio, and filament size too. Wadeby Wade - Reprappers
The Reprap host doesn't display the Stl properly at all, it's not even close. It might be a binary vs ASCII thing, but it works in Skeinforge, so I just use that.by Wade - General
Simon, that looks great, looking forward to seeing how well it works, as I need to make something a little tougher than just PTFE and brass. Mike, I'm interested in the glass nozzles - I've been thinking about a glass insulator for a while, but haven't found a good way to attach the nozzle. Any chance you could post some photos as well? Perhaps a compression fitting on the cold end would helpby Wade - General
Old reply, but a few washers under the idler block lets you load filament on the fly. I left some extra travel in the design to allow for variations; reducing the idler block travel makes it easier to load filament. Also, if you can't find strong enough springs, just bolting the idler directly will likely work, especially if you use only 2 diagonal.by Wade - Mechanics
Threaded rod works fine on the Mendel and Darwin Z axis; resolution is about 0.003 mm/step on a direct threaded rod drive. Most people have trouble running the X and Y fast enough with threaded rod though, thus the belt drives.by Wade - Mechanics
Interesting! Did you start with the Solid Edge files?by Wade - General
The whine is from the PWM frequency, by default it's about 1 kHz. You can increase it if you want, but it works fine for me. I use an extruder controller board as well, with the PWM set to 0.75, but that will depend on your stepper. I'm also using some pretty strong steppers - 5 kg*cm, and a geared extruder. With the current set correctly, you should be able to extrude slowly at first withby Wade - General Mendel Topics
It's ASCII, but the difference is the Arduino serial monitor doesn't send CR/LF characters at the end of the line. Add those in and you should be fine! Wadeby Wade - General
Try turning the stepper current up until the motor starts to overheat, then turn it back just a bit. If your extruder is PLA, make sure you don't melt it. Then run it as slow as possible, about 4 mm/s. Finally, if it still won't work, you can try drilling out the nozzle; 0.5 mm is probably the smallest you want to start with, larger will be easier. Then print a geared extruder. I had exactby Wade - General Mendel Topics
Hey, I'm in Vancouver as well, and was getting ready to post a set of Mendel parts on Ebay. Email me at wbortz at gmail dot com, and we'll see if we can work something out.by Wade - Wanted
Oh wow, I hadn't seen the photos when I first replied - that's a huge thermocouple! Assuming the wires are chromel and aluminel all the way back to the pigtails, you can dispense with all that metal on the end and just use the wires themselves. This is the technique I use to attach the thermocouple wires to my extruder nozzle: Wadeby Wade - Controllers
Trim away! You can even use the trimmings as another thermocouple, just crimp the ends together in whatever you want to measure.by Wade - Controllers
Actually, with some low profile Molex connectors and switching the circuit board mounting sheet to the other side of Mendel, you can use the ATX power supply connected directly to the motherboard, no electronic modifications required. I also use the RJ45 connectors on the endstops, but only on the stepper driver side - I just solder the endstop wires to the pcb to save space. Here's a photo:by Wade - Controllers
Nophead had done long, thin stainless barrels; read his blog for details. It takes a lot of Q to keep one side hot and one side cold; he used very thin SS and heat sink plus fans.by Wade - General
One trick I've been using for the simple PTFE - Brass extruders is to use a much wider barrel than PTFE bore. IE, I use a 3 mm bore in the PTFE, and a 4 mm bore in the barrel. Seems to really reduce the friction, and also gives me more room for mis-alignment between the PTFE and barrel. This doesn't work well with an M6 brass barrel though; I usually make my barrels from 8 mm brass stock, andby Wade - General
Actually, both GCode's from Skeinforge are correct - the difference is that the first example, there is a combined X, Y and Z move all together. Skeinforge correctly adjusts the feedrate so that the Z component doesn't go past the set point. In the second example, the X and Y moves are 0, due to the homing code M105, so you get 60 mm/min, since it's a straight vertical movement. The problem isby Wade - Skeinforge
You can either move the positioning of your STL file using a mesh editor like Blender, or activate the Multiply tab of Skeinforge, set it to 1 by 1, and center it where you like.by Wade - Skeinforge
If there's no voltage at the pin on the Arduino, it must be a programming error. Try changing the pin to a different pin in the test code, and see if you can get a different pin to work. Could be that pin was damaged somehow. Wadeby Wade - Reprappers
I use a non welded thermocouple for temp control, and have the software look for out of range temperature values. If either of the thermocouple wires come loose, or things get too high, I shut down the heater. If you're using a Makerbot motherboard with an ATX power supply, you can even turn off the power supply automatically. Wadeby Wade - Plastic Extruder Working Group
Got a green light on your motor board? How about voltage on the arduino pin? Check your pin defines too, maybe it's set up to use a different pin. Wadeby Wade - Reprappers
More repraps, which was my plan from the start, but also some nIce gears. Wadeby Wade - Reprappers
Nope, the thermocouple wire should be bare at the tip. It doesn't matter if the two wires actually touch inside the hole, as long as there is a K to Brass to T connection in there somewhere, you'll get the average voltage. This does require that your nozzle is electrically insulated from the rest of your electronics though - make sure you don't have a short from the nichrome to the nozzle. Andby Wade - General
Actually, something that has been working flawlessly for me is a Nasa technique for attaching thermocouples to rocket motors - Basically you drill a 0.5 mm hole in the side of your nozzle, not all the way though, insert the 2 thermocouple wires, and peen them in there. It works great, and if you use non-welded thermocouples, you get an automatic fail-safe - if one or more of the wires comesby Wade - General
rhmorrison Wrote: ------------------------------------------------------- > To add the PTFE barrel to Wade's extruder you > insert it into it's position and then use a drill > with a ~4mm drill bit to drill the holes through > the PTFE barrel. Then add two M4 screws with > nuts. The heads of the screws should be on the > side with the gear. Guess I need to update the wiki agaby Wade - Plastic Extruder Working Group
I like it - looks pretty solid. I've been thinking of glass or ceramic for the heat insulator as well. A bit of fiberglass insulation, and you'll be good to go! Wadeby Wade - Plastic Extruder Working Group
Nophead's your man, in terms of who can test the parts, as well as who's your best bet for getting a quality set of parts! I'm curious though, the torque values seem a bit low - 50 mNm, vs 260 mNm for the steppers I use on my X,Y and Z axis, or 500 mNm for my extruder stepper. I suppose a closed loop system will use the full torque when it's needed, so they'll probably work just fine. How muchby Wade - Wanted
[0] RepRap Host [0] RepSnapper [1] Skeinforge [0] Custom Program that I Don't Distribute - same for me, but I put my initial setup routine in start.gcode, so it's all automatic. Wadeby Wade - Reprappers
3dptools Wrote: ------------------------------------------------------- > I would strongly recommend not to use any PEEK or > PTFE parts in your heated part of the extruder. I > use a stainless steel / aluminum combination in my > printers: > > www.3dp-tools.com Can't agree with that one - I've printed 3 Darwins and 2 Mendels using just simple PTFE and brass hot ends. They wby Wade - Reprappers
I'm using Makerbot electronics and steppers on my Mendel, and it runs at 50 mm/s no problem. One thing I did change was the extruder though - I use a 5 kg*cm Kysan stepper for that, and my geared extruder. Wadeby Wade - General Mendel Topics
Good that it's working for you! At Maker Faire last weekend I was sitting next to some students with another Mendel design that was over constrained on the X and Y axis, and they were having a lot of trouble getting it to run smoothly. I think they'll get it running in the end, but it's certainly not the easiest way to build one of these machines.by Wade - General Mendel Topics