I tried plywood the first time around and found it to be miserable. The heat from the PLA causes the layers of the plywood to separate over time. This means that you get an uneven bottom surface which can mean that prints can slump over. Also, I live in the south east US, with the humidity we have here, plywood likes to warp. I switched to MDF and the problems went awayby criswilson10 - Mechanics
To Dman Firing wax through an HP cartridge is difficult because it only does microheating at the nozzle and to get to that nozzle the fluid (ink, wax, glue, whatever) has to be able to flow through a narrow (10 mil I think) spiral channel. If you want to do wax, I would go with the reprap extruder at a lower temp. To Johnrpm and others considering nylon powder The old infrared lamp design does wby criswilson10 - Powder Printing and Selective Laser Sintering
I haven't ever used a lexmark for powder printing, I've always used HP because you can order empty cartridges and fill them with whatever you want and HP offers tech papers that explain how to fire the jet(s). Anyway, the hardest parts of building a 3d powder printer are the 3 axis platform, controller hardware, and controller software. Reprap has pretty much knocked our 90% of the work. I'llby criswilson10 - Powder Printing and Selective Laser Sintering
You would also need to take into consideration the thermal properties of your rope or belt. A plastic or nylon one may also melt at the temperatures of the heated PLA. Plastic or metal would both stretch at the higher temperature so tensioning of the rope/belt could be an issue.by criswilson10 - Mechanics
The STP-42d265 is just barely powerful enough to be used for a reprap, brand new they can hold about 0.16 Nm (1600 g*cm). After some use they drop down to about 0.1 Nm. You are going to have to use a lot of lubricant to keep a reprap moving with that little motor. Personally, I would use a different motor for a reprap and use that little motor in a small robot or some other project.by criswilson10 - Mechanics
Those printer motors probably have some labeling on them that says something like PM55L-048-E. Post what is on the label and I'll see if I have the specs for them. Typical printer motors have the following specs +2 to +24 Volts, uses 600 mA per phase, with a coil resistance around 30 ohms (unipolar) or 6 ohms (bipolar). Holding torque is probably around 0.2 Nm for unipolar and 0.1 Nm for bipolarby criswilson10 - Mechanics
There is a company called "Small Parts, Inc." that sells needles online. I'm not sure if they sell the sharp injection type or not, but I have ordered blunt needles from them that were 28 gauge. I seem to remember that they had the blunt needles with luer lock from sizes 10 to 32 gauge. The price was reasonable, they shipped fast, and because they were blunts there was no paperwork involved. Aby criswilson10 - Mechanics
Check around on ebay. I bought a lot of 32 for $10. It was more bearings than I needed, but I couldn't beat that price. And those extra bearings wound up in other projects.by criswilson10 - Mechanics
Home built powder machines aren't that hard to make. It is essentially an inkjet print process. HP even sells empty inkjet cartridges that you can fill with glues to spray out. So you rake a layer of powder out over a plate, spray the print area with glue, lower the z axis a bit, rake powder over the plate, spray glue, and so on until you have your finished piece. Of course, the powder makes aby criswilson10 - General
"Just for fun what more do you guys think we need in terms of technological development to achieve directed bio development...... ?? " Better designed "print heads" that could handle single cell placement without killing the cell from pressure or heat, heads that don't clog up, and amazingly fast nanopositioning would all be nice.by criswilson10 - Tissue Engineering
Those of us doing bioprinting at the moment, are mostly using epithelial cells which are cheap and easy to harvest and grow. From those cells we can make replacement skin for burn victims and replacement veins and arteries for bypass surgeries. A growing area of research seems to be in making replacement colons as well. But something like skin that most people consider to be simple, is not so sby criswilson10 - Tissue Engineering
I guess we better add a reprap MRI project to the table so that you can the 3d pattern for your replacement organs then.by criswilson10 - Tissue Engineering
As someone who has designed and built cell/tissue/DNA printers, I can tell you that the difference between the bioprinters and reprap is basically the print head and the material being "printed". So in theory a reprap could one day do it. I would try to keep the name reprap out of that field of research if you can because the next thing you know people will be screaming that reprap is being usby criswilson10 - Tissue Engineering
I've used conductive adhesives (mostly silver with an acrylic resin) to do emergency repairs, but never for an entire circuit. The adhesives usually have a high resistance, which is an issue if you are moving a lot of power through them. I did try it one time on a trace from an L298n to a stepper motor - the adhesive lasted about 10 seconds and the motor didn't run well during those few seconds.by criswilson10 - Plastic Extruder Working Group
In the US, most of the PLA is made by Nature Works.by criswilson10 - Plastic Extruder Working Group
Can it be done? Yes. Is it cheaper? That depends on the cost of your time. It also depends on whether or not you can find an m8 die - they are not common in the USA. Most likely you will need to replace the die after you have used it 20 or so times. If you chamfer the rod tip a bit with a file before you start, it will be alot easier to get the die going and use lots of oil or tapping fluid.by criswilson10 - Plastic Extruder Working Group
Did you put a load resistor across the sense line so that it would know to send power?by criswilson10 - Controllers
I'm having flashbacks to an old epson stylus printer from the early 90s... If that is what the motors came out of then they are hybrid steppers (unipolar or bipolar) and run on 0.5 Amps and 12 Volts. They were low torque and maybe 4.8 degrees per step. I doubt that you are going to find a data sheet online for them because of their age, but a little work with an ohm meter and you can probably creby criswilson10 - Controllers
I don't know if you would want to do soldering in your oven and then cook in it again...that could cause some health issues and/or spouse issues. But, I do use a toaster oven to do soldering with. I bought it second hand at a yard sale for $5 (US). The temperature setting on it wasn't exactly accurate (+/- 50 degrees Fahrenheit), but it worked. I later added a thermocouple to the inside of theby criswilson10 - General
Electrical connection to the metal was made with a welding type jumper cable. The bed was insulated with 1/2 inch thick plastic. For concentric circles, as mentioned above, you cut the smallest one first, but they are limited in size based on the accuracy of your cutting head. IIRC, a 1/4 inch diameter circle was the smallest the design would do. Anything smaller than that didn't really come ouby criswilson10 - Mechanics
I built a cartesian bot a few years back for sheet metal and it used EDM (electrical discharge machining). It wasn't exactly a home use machine because of its size and power load. I suppose those you could easily mount an arc welder with a carbon cutting rod to a cartesian head and cut thin sheet metal pretty easily.by criswilson10 - Mechanics
For me, it doesn't seem to matter if I am using a reprap, cnc mahine, laser cutter, or powder printer - setting up the files to print always seems to take the longest amount of time. Even if the output takes a day to be formed, it is still shorter than the time I've spent designing it and orienting it properly. Faster speed is always better, but from my standpoint as an engineer, if the physicby criswilson10 - Reprappers
All of the documentation I see on the smc44g is in German, which isn't my native language so I can only roughly translate the following pdf file at: It's a 0 to 40kHz bipolar chopper for 5v or 24v bipolar steppers The motor wires plug into the A, A/, B, and B/ on the right hand side of the controller. The 24V input power and ground go underneath those. On the left side you get to pick if you wby criswilson10 - Mechanics
Your answer is on the Sanyo Denki webpage But here is the summary Orange and Blue are one set of wires Red and Yellow are the other set Black and white are the commons (white may be tied internally) Clockwise full step firing order is Red Blue Blue Yellow Yellow Orange Red Orange I'll let you figure out the half step orderby criswilson10 - Mechanics
Flexible superglue... Strip about an inch off of the smooth backside of one end of the belt leaving the teeth. Strip the same amount off of the other end of the belt on the tooth side. Test fit them together and see if you need to remove a tooth or two. Smear the stripped faces with glue and stick them together. Hold or clamp until dry. Some tips: To strip the belts use a sharp razor blade orby criswilson10 - Mechanics
I usually breadboard new circuits that I haven't built before, before I move them to perfboard or PCB. I've pushed breadboards up to 6 Amps before they started melting so it should be able to take 4 Amps. I would definitely put the caps on that jbb mentions and definitely heat sink the 298s. The diodes will be fine unless your motor shorts out and it's easier/cheaper to replace the diodes than tby criswilson10 - Controllers
I'm not sure where a list of readings would even begin if you wanted to learn all of the mechanics, electronics, and software. To learn the electronics I guess you could start with the pseudobible Art of Electronics. To learn the sanguino/arduino I would say to get an arduino kit, and work through the examples. Or go even more basic and get an AT8 microcontroller and programmer and learn from itby criswilson10 - General
I'll be glad to help design a device to spit out ABS powder, but I need to know what particle size you need. It would also be nice if you could tell me at least one form of ABS supply that will be ripped down to powder. I'll go on and warn you that a grinding type powder producer is going to be loud and use a lot of power. It probably also require routine blade sharpening. If you want to go wby criswilson10 - Plastic Extruder Working Group
"Where do the air bubbles go in a wine press? Is there a way for it to escape out the top?" The larger ones get caught in the plastic at the top and due to a rather large head space, they never make it out of the nozzle. The smaller ones, do go out through the nozzle mixed in with the molten plastic. It's not a problem for their application, but it would be a problem for making reprap filament.by criswilson10 - Plastic Extruder Working Group
I went and tracked down my old grinder and press; and talked with the people that use it. According to those that use it, the grinder works great on hard plastics like acrylic and lexan, but it doesn't turn soft plastics like milk bottles and drink bottles into powder very well. At first they were still grinding the old drink bottles down as well as the grinder would do it and then melting them,by criswilson10 - Plastic Extruder Working Group