Well my plan is to finish building the one I'm working on now and then start replacing metal parts with reprapped ones.by criswilson10 - General
Wow, someone that knew I was talking about creep. :-) You must be an ME. Anyway, it would work. For the long term replicatable parts, I was considering printing out 6 inch (15 cm) long beams with joints on the end to let the beams snap together like puzzle pieces or lego pieces - using glue, screws, pins, or whatever to hold the joint. The thing holding me back on the design is knowing the weigby criswilson10 - General
Corn starch dissolved in water to make a paster works well tooby criswilson10 - Plastic Extruder Working Group
I've built a small grinder before that reduced plastic stock to powder and I have built melter/extruder for plastic as well. The grinder cost was around $100 (US) and the melter/extruder was around $100 (US) as well. So it isn't exactly cheap even when made from scrap materials. It also involves having a machine shop to build the grinder. Although, I suppose that if you have enough experience witby criswilson10 - Plastic Extruder Working Group
Could it work? Yes. Would it be cost effective? I dont' think so. Personally I would rather have to cut the steel rod twice then have to glue 4 pieces of acrylic together and then have to worry about the glue joints breaking. Plus, acrylic (or any non thermoset plastic) tends to warp over time when under load. Although I have considered using thick wall PVC plumbing pipe.by criswilson10 - General
Extruding solder most solder is going to be a pain since most solder is designed to stick to copper. And it is going to clog up the nozzel unless you blow it out with compressed air or something when you are done. As far as connecting copper wire to nichrome wire goes, the solution that works best is a mechanical crimp, but I have also used a brass screw and nut before with the nichrome wire aby criswilson10 - Plastic Extruder Working Group
To answer the part about countersinking: Countersinking is relatively easy with a hand held drill. You might want to practice on a few holes in scrap first so that you get the feel for keeping the drill vertical. Most likely the first couple of holes you will not countersink enough and will have to go deeper.by criswilson10 - General
Polishing will help, ideally you want a guide rod to be within +/- 0.0001 of an inch in diameter (can't remember how many microns that is). An appropiate sized bronze sleeve bearing will also eliminate alot of the friction. A chromium steel rod with a bronze sleeve bearing and a little lithium grease has very very very low friction - that's why they are used so much in printers. If you are usinby criswilson10 - Mechanics
Those surplus printer rods were probably chromium steel - the stuff they make hand tools out of and chromium is tough to cut through by hand. As for your threaded rods bending, if you get the stainless steel rods they do not bend as easily. If you got your threaded rod from a hardware store it is probably not stainless and it will bend pretty easy - of course you could anneal it...by criswilson10 - Mechanics
Sergei, To quickly answer your question, I would say use a TIGG or acetylene. For a longer answer - keep reading. If you are going to braze aluminum then rough it up first to remove the aluminum oxide off the surface. You can rough it up with steel wool, a wire brush, sandpaper, bastard file, dremel tool - whatever. The shinier the better, just like when soldering. The same applies to brass.by criswilson10 - Plastic Extruder Working Group
I didn't have to harden the rods from McMaster, although I guess it wouldn't hurt to do it if you want to. If you want to look at the specified rod from a bending point of view, the rod is well over specified for what it is supporting. I think the decision for the rod diameter was based on availabilty and ease of use instead of load. If it was based on loading, then it would probably use a 4.5mby criswilson10 - Mechanics
First, make sure your stages move smoothly by hand. If they are harder to move at one point than the others, then your rod could have a bend or a defect in it. If it is a bend, see if it is a physical bend or if the rod is bending due to loading. If it is a physical bend replace the rod, if it is bending due to loading, then check the alignment and/or end play. If there is a defect in the rod liby criswilson10 - Mechanics
I've been using Rhino for about 2 years now and it seems alright. I'm not as fond of it as AutoCad, but I've been using AutoCad for about 20 years, so I might be a little bit one sided. What I can say that I really like about Rhino is how well students that are new to cad work take to it. When we switched them from AutoCad to Rhino, they produced 3d drawings faster with more detail than they hadby criswilson10 - 3D Design tools
I was wondering enough about the contact angle, that I went ahead and did them out of curiosity. The reprap stepper motors have a maximum torque of 1.2 Nm The reprap 6mm wide MXL belt has a tooth torque rating of 0.182 Nm So 1.2/0.182 gives a minimum of 6.6 teeth which would be a minimum mesh of 7 teeth. 7 teeth is about 50% of the darwin capa x or y motor pulley. So you would need to use a diffby criswilson10 - Mechanics
That is the rule of thumb in designing with pulleys - get as much contact as you can to prevent slippage. Since these are toothed belts, slippage is minimized by the teeth and belt tension, but you have to worry about tooth shear.by criswilson10 - Mechanics
I agree that would probably work. The reason I use(d) 2 idler posts is to give the belt and pulley more surface area contact. This lowers the shear force applied to the teeth on the belt. Essentially, the more belt you have in contact with the pulley, the lower the chance of shearing off the teeth on the belt. I know at the time I didn't sit down and do the math on the minimum contact angle neby criswilson10 - Mechanics
OK, so here are some pictures of what I was talking about above. And while you could get away with only 1 idler, 2 idlers kept the belt from moving around (vertically) when changing direction.by criswilson10 - Mechanics
It completely eliminates the need for a tensioner arm and there is plenty of room for the electronics with a NEMA 23 or NEMA 17. I've built a z-axis like that before and it works well. As a matter of fact, I think I have one in my storage closet. If I do, I'll pull it out and post a picture of it and the details.by criswilson10 - Mechanics
Along with backlash, you would have to take into consideration gear mounting and clearances. Most gearing requires a clearance of 1mm or less which is easy to do if you have the right equipment, but a real pain to do for most home users. I'm not saying it can't be done by a home user, I'm just saying it is extremely frustrating. As for stablizing the base, I have another z axis machine that I bby criswilson10 - Mechanics
As someone who has built PCI cards for PCs and even built cards to plug into the parallel port (using the 74367 chip) to control motors, I can tell you first hand it is easier to use a microcontroller to control the motors and heater. You screw up a circuit for a microcontroller you are out maybe $10, you screw up a circuit on a PCI card you are out a MOBO or more. I've connect up motors to parby criswilson10 - General
Wow, I didn't realize conduit was that cheap. I must remember to ask the contractor I use why he is charging us so much for conduit. That is a pretty good cost savings. Thanks for edumakatin me.by criswilson10 - Mechanics
Rodzite is correct, the wall thickness is 0.126" or 3.20 mm. I forgot to divide by 2 when I measured the conduit beside me - duh! ;-) I'll agree that it could be used and if you can find someone that does conduit work to give you their scrap pieces for free it would be great; otherwise, conduit can get expensive. I've heard of 1/4" ID aluminum conduit, which should have an OD close to the M8by criswilson10 - Mechanics
American conduit is usually defined as thin walled piping for holding electrical wires. It is usually made of aluminum, steel, or PVC. The internal diameters start at 3/4 of an inch and go up to at least 8 inches. The one to two inch diameter stuff is the most common. By thin wall, I mean that the 1 inch (27mm)steel conduit has a wall thickness of 0.315 inches (6.4mm). It bends, cuts, and threadsby criswilson10 - Mechanics
I've been through the stepper versus constant dc motor debate before and ultimately the constant dc motor with optical encoder wound up being only a few pennies cheaper (including the drive electronics and programming time). Which is great if you are mass producing a product, but for limited builds, it may not be worth the effort. But if you feel more comfortable using a dc motor with encoder tby criswilson10 - Mechanics
It is normal for a stepper control chip to get hot. I've been burned by a few in my time. But you should use a large heat sink on the control chip and use some thermal grease between the chip and heat sink. The chips will also overheat if the motor is drawing too much amperage. Make sure that your controller chip is rated for your motor. And of course, there is always the possibility that yoby criswilson10 - Controllers
I'll agree with the double sided boards being a pain to make at home. I'm in the process of converting some of the double sided stuff to be single sided boards as I get time.by criswilson10 - Controllers
The files for mcwire are on sourceforge at:by criswilson10 - Mechanics
New to the group, but I deal with power supplies all of the time. It sounds like you've got some soldering issues, but just in case check all of these. First thing is to check you voltmeter and make sure that it is actually displaying the voltage correctly. If you another voltmeter handy just check the same voltage with it as well and see if you get a different result. If you don't have anotherby criswilson10 - Controllers