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People building or using RepRaps.
Re: Extrude without filament - 14 years ago
It sounds feasible. I'd consider making a heater barrel with a rectangular center hole. Perhaps soldered together from brass bar stock. You could taper the hole so that it was 1/8" square at the bottom and 1/8" (3/32" + 1/32" for clearance) by some convenient width (1/2"?) at the top. If you know someone with a lathe you could turn and thread the bottom for a standard nozzle.by JohnWasser - Mechanics
Re: What nozzle design would the community like to have machined?
- 14 years ago
The idea of an adapter would be OK for people who like the Mark 5 design and can spare $100 for the hot end kit (+17.50 for a relay board). Personally, I don't really like the bottom (heater/nozzle) half of the new Mark 5. The 5 ohm 10 watt resistors are being run at 28.8 watts (almost three times their power rating). Part of the reason you need to dump so much power into the resistors is thby JohnWasser - General
Re: What nozzle design would the community like to have machined? - 14 years ago
Having seen the new MakerBot Mark V extruder hot end I'd like to see a design with some of the advantages while using many of the previous design's parts. What I envision is a stainless-steel-lined-with-PTFE replacement for the Mark III/IV PTFE insulator. The top of the stainless-steel part would be the diameter of the old PTFE insulator. The rest would be turned down to improve its insulatingby JohnWasser - General
Re: how about unassembled? - 14 years ago
Their website also offers the same thing in kit form: $945.00 (without motors and electronics) $307.75 (Motors, electronics and power supply)by JohnWasser - For Sale
Re: Motherboard schematics possible mistake - 14 years ago
I agree. Even on the schematic it shows inconsistent labeling: (PCINT24/RXD0) PD2 |--- Pin 11 INT0 (PCINT25/TXD0) PD1 |--- Pin 10 TXD (PCINT26/INT0) PD0 |--- Pin 9 RXDby JohnWasser - Controllers
Re: New extruder concept - 14 years ago
You should get better performance by insulating or at least sanding off the fins on the resistors. The fins are there to dump heat into the atmosphere so that is heat that is just wasted when you are using the resistors as contact heaters.by JohnWasser - Plastic Extruder Working Group
Re: Nichrome Wire Questions - 14 years ago
HSRepProject Wrote: ------------------------------------------------------- > The temperature that nichrome reaches is > determined according to wattage, correct? The temperature depends on power density, not just power (Watts). If you have a 6-Ohm piece of fine gage nichrome that is 3 cm long it will get hotter than a 6-Ohm piece of heavier nichrome that is 30 cm long, even though both aby JohnWasser - General
Re: Nichrome Wire red hot - 14 years ago
The cold resistance is the important measure. You want the nichrome to measure close to 6 ohms when cold. With the fiberglass insulated nichrome I got from MakerBot Industries the length was around 30cm. If the nichrome is very thin (has a higher resistance per unit length) the 6 ohm length may be too short: the power may be concentrated enough to cause the wire to overheat and glow. You canby JohnWasser - Reprappers
Re: What is needed to build up a robot? - 14 years ago
Hmmm... Looks more like an advertisement than a question. :-/by JohnWasser - Robots!
Re: MakerBot Stepper Controller Help - 14 years ago
Katai Wrote: ------------------------------------------------------- > I got some advice to switch > out the IC3 5v regulator (my multimeter shows its > only outputting 1.5v), so maybe I can salvage that > when I get the parts. If you are running the stepper from a PC power supply you can get 5V from the red wire of the power connector. The MakerBot stepper controller makes 5V fromby JohnWasser - Reprappers
Re: Macgyvering a thermistor for Rapman - 14 years ago
Just thought of a good MacGyver solution: Pull the thermistor out of a remote-probe oven thermometer. You will have to determine resistance and Beta by experiment but it should be a reasonable replacement. Typically the pointed probe tube is crimped over the silicone-insulated cable. A sharp edged file should let you weaken the tube below the crimp and break it off.by JohnWasser - General
Re: Which thermistor - 14 years ago
If you can't find the EPCOS B57560 series there are lots of other choices. The Digi-Key online part selector, for example, has a good selection of 100K thermistors with an upper limit of 250 to 300 degrees. They should all work fine in an extruder.by JohnWasser - Controllers
Re: Nichrome Wire - 14 years ago
Looks like Nichrome 60 has a slightly higher resistance than Nichrome 80 of the same diameter. For example, 30-gage (0.010) wire is 6.75 ohms per foot in 60 and 6.5 ohms per foot in 80. Both melt way above the safe temperature for Kapton so either should work.by JohnWasser - Reprappers
Re: Stepper Controller Board not working? - 14 years ago
That's the voltage regulator that provides 5V from the 12V supply. That would be the chip to replace if you can't find 5V on any of that chip's pins when your board is powered. If the 5V regulator is working then it is probably the stepper driver chip that failed.by JohnWasser - Controllers
Re: Tear Drop Holes. - 14 years ago
The top of a horizontal hole has no support. Putting a "roof" on the hole reduces the maximum overhang angle to 45 degrees.by JohnWasser - General
Re: MakerBot Stepper Controller Help - 14 years ago
Since you have definitely identified one specific driver board as faulty you should take some time to examine the solder joints. From observation of other problem reports I'd say that most failures are due to solder problems. Make sure every solder joint looks shiny and has filled the space between board and pin. Also look for solder bridges between adjacent pins. If you find a bad joint youby JohnWasser - Reprappers
Re: MakerBot Stepper Controller Help - 14 years ago
Since you have three stepper drivers, three steppers and three ribbon cables you should swap parts around to determine what piece is faulty. If it's a ribbon cable you can fix it. If it's a motor or driver board you should contact MakerBot about a replacement.by JohnWasser - Reprappers
Re: Why use motor control boards? - 14 years ago
I think the advantage of the IC stepper controllers is that they have adjustable current outputs. That allows the use of a high drive voltage to step quickly followed by a lower current to keep the steppers from overheating.by JohnWasser - General
Re: hand held 3D scanner - 14 years ago
I downloaded the program to my Windows XP laptop (Dell Inspiron 600m) and it said that I did not have enough GPU capability to run. I guess this program is not for me. viktor Wrote: ------------------------------------------------------- > hey guys check this out > > ee-vi3dim-demo-download-dwnhmlch.htmlby JohnWasser - 3D Scanners, Book Scanners, and Optics
Re: Request: Mosfet PWM heater cricuit - 14 years ago
If you are talking about the extruder, the Extruder Controller firmware implements the PID loop. The "B" output of the Extruder Controller board is an analog (PWM) output. If you are talking about a heated build platform, the Extruder Controller also implements the PID loop for that but the "A" output of the extruder controller board is a binary (0/1) output so it turns ON for values of 128 orby JohnWasser - Controllers
Re: Generation 3 electronics HELP! - 14 years ago
The minor mismatch in RXTX versions should not cause a problem (at least it doesn't on my MacBook Pro). It looks to me like either you have not selected the serial port that corresponds to the USB-to-TTL-Serial cable OR the cable is bad OR the cable is plugged in incorrectly (should be GREEN on the right and BLACK on the left). Double-check all that the try to upload fresh firmware to the Motheby JohnWasser - General
Re: hand held 3D scanner - 14 years ago
I'd prefer a Mac OS X solution but the fact that it was developed for Linux first bodes well. Perhaps I'll drag out the Windows laptop and give it a try.by JohnWasser - 3D Scanners, Book Scanners, and Optics
Re: hand held 3D scanner - 14 years ago
From the screen shots it does look like Vi3dim could work at least as well as the David software and doesn't require structured lighting (a laser line or sharp contrast line). The screenshots show an object sitting on a black and white checkerboard grid. The grid and object are apparently rotated by hand. and the software uses the image of the grid to get scale and position information about tby JohnWasser - 3D Scanners, Book Scanners, and Optics
Re: PicoPSU power supply. - 14 years ago
You still need a 12V 10A power supply to provide power for the adapter which then provides various other voltages, none of which the RepRap needs. The RepRap only uses the +12V supply so you might as well skip the expensive step of doing the conversions. Standard ATX power supplies are only "big" because that is the size that IBM used in the old IBM-PC/AT back in the 1980's. If you want a smalby JohnWasser - Reprappers
Re: Motherboard firmware / Sanguino problem - 14 years ago
When uploading firmware to the Motherboard, I jumper the two "autoreset enable" holes near the serial connector. This allows avrdude to automatically reset the Sanguino at the right time. If I ever have to take the Motherboard off I'll slder a couple of pins in those holes and have a jumper handy.by JohnWasser - Sanguino(lolu)
Re: Heater idea - 14 years ago
I'd be surprised if a ring crimp (or even several) would have enough thermal conductivity to move the heat of the resistor to the heater barrel. The machined aluminum completely surrounds the resistor and the heater barrel. Aluminum foil packed around the resistor is used to increase the thermal conductivity between the resistor and the block. If you don't have the means to machine aluminum yoby JohnWasser - Plastic Extruder Working Group
Re: Mendel Extruder Head Temperature Sensor - 14 years ago
The default "Generation 3" electronics connect the extruder temperature sensor thermistor through the Extruder Controller. See: If you wish to use a thermocouple you will need the optional Thermocouple Sensor 1.0 board:by JohnWasser - General Mendel Topics
Re: Nozzle and Barrel, or nozzle/barrel - 14 years ago
The one-piece arrangement is less expensive. It also has less thermal mass so it probably heats faster. It has a smaller exposed face so it probably takes less heat to maintain temperature.by JohnWasser - General Mendel Topics
Re: Imperial sizing for Mendel parts - 14 years ago
I think the only thing you have to do differently is the "steps per mm" setting on the Z axis. I've already bought 5/16" threaded rod, nuts and washers for my Mendel frame. As soon as I get my MakerBot to print larger objects like the vertices without warping I'll try it out. I don't expect it will be a problem. I found several "Metric/English" conversion tables on the internet. Here is whatby JohnWasser - Reprappers
Re: Keling 23H51-24-08B Stepper Motor Question - 14 years ago
They show both the Bipolar Series connection: A+ Blue (coil) Red - Yellow (coil) Green A- B+ Brown (coil) Black - Orange (coil) White B- And the Bipolar Parallel connection: A+ Blue/Yellow (coils) Red/Green A- B+ Brown/Orange (coils) Black/White B- I don't know why their diagrams don't match the arrangement that works for you.by JohnWasser - Stepper Motors, Servo Motors, DC Motors