There's a design that moves a single guide rail in X and a single guide rail in Y and uses a bowden extruder, and moves the Z axis downward during printing. A guy on Google+ named Shauki Bagdadi (https://plus.google.com/u/0/+ShaukiBagdadi) has built such a printer using cables to drive the X and Y axes and he runs the thing at 250 mm/sec. I suggest you get on Google+ 3D printing group because hby the_digital_dentist - Mechanics
A few comments: One of the first problems 3D printing noobs run into is getting the prints to stick to the print bed. Some people spray their bed with hairspray, others use "ABS juice", others use glue sticks. Kapton tape works well and isn't as messy as any of those, but costs a little more. The heated bed is necessary to keep the ABS part stuck to the kapton tape on the surface of the bed. Iby the_digital_dentist - Mechanics
That's encouraging! The new motor is in and bolted to the machine, waiting for the driver to arrive later this week. The driver is good up to 50V, but my power supply is about 32V under load. I'll try the driver and power supply with both motors. If I have to I can build a higher voltage supply- I have a transformer that can easily do the job.by the_digital_dentist - Mechanics
I'll be installing a DM542 driver module (http://www.americanmotiontech.com/upload/Manuals/DM542m.pdf) and replacing the AT Mega2560/RAMPS boards with a SmoothieBoard. The SmoothieBoard can provide up to 200k pulses per sec to the steppers compared to the 40k pulses per sec with the ATmega2560. That means I can increase microstepping which is supposed to help with vibration, especially at low sby the_digital_dentist - Mechanics
OK, after some study I believe I have a handle on the vibration problem. It is inherent in the steppers- the detent force required to make it go from one step to another causes the vibration at low speeds and resonance effects cause it at higher speeds. The driver on the RAMPS board is no help- it is just a dumb driver that is capable of microstepping. All is not lost! A decent stepper driverby the_digital_dentist - Mechanics
You have two issues: adhesion to the bed and delamination. Adhesion is a matter of getting the right material on the bed surface and leveling the bed accurately. I like kapton tape and rarely have adhesion issues when printing ABS on clean kapton tape. I wipe the bed with acetone before printing (don't use finger nail polish remover- it contains stuff like glycerin that won't help parts sticby the_digital_dentist - Printing
Quoteerosnicolau Hi, there, I've been researching different 3d printer configurations lately and I saw pretty different approaches in how to choose what's fixed and what's moving in a 3d printer. Basically, 2 rules apply generally: - the lighter the moving parts, the speedier the print can be - the lighter the moving parts, the less inertia, resulting in the more precise printing. ... Thanks foby the_digital_dentist - Mechanics
Well, screw drive is definitely noisier than belt drive. I installed the screw drive mechanism last night and tried a test print. At certain speeds the thing vibrates a lot. When you think about it, it makes sense because there's no belt to buffer the vibration from the motor- just a lot of metal to metal contact throughout the drive mechanism. One interesting change in the sound profile is tby the_digital_dentist - Mechanics
Update: the screw drive vibrates badly at some speeds. I decided to beef up the undercarriage plate to 1/4" cast aluminum tooling plate. I also replaced the printed plastic standoffs with aluminum tubing. The new configuration has the reference side set up with a 280mm long piece of aluminum tubing for the standoff screwed to two bearing blocks. The other side has a short piece of tubing scby the_digital_dentist - Mechanics
You can print with ABS on PIR (polyisocyanurate) foam without heat. I have not tried printing on it with PLA. PIR foam is sold in big sheets for building insulation. In the US a 4' x 8' x 1" sheet costs about $15 (PIR foam sheet at Home Depot). You can cut it to the size you need with a razor knife. Stratasys FDM machines print on polyurethane foam. I've been told they charge about $70 US fby the_digital_dentist - Mechanics
If you don't bury the nozzle too deeply the effect is to push the foam down without tearing it up. In the first video you can see an area in the upper left corner of the foam where I buried the nozzle too deeply and it tore the foam up a bit. The foam is soft enough that it gets out of the way when the extruder is pushing plastic against it. I did not have any problems with clogged nozzles- noby the_digital_dentist - Mechanics
Any CAD program should be OK for any size bed. I have been using DesignSpark Mechanical a lot and find that I rarely run into its limitations. If you're looking for really simple, try Sketchup.by the_digital_dentist - Mechanics
One more thing... the main argument against a large print envelope RepRap type machine is the mass of the printbed that has to be slammed back and forth. The mass can be reduced significantly and the printer simplified by printing on room temperature PIR foam instead of a heated metal or glass bed. I have done it, it works, but you have to give up the super shiny, smooth bottom surface of theby the_digital_dentist - Mechanics
My experience with z-axis motors getting out of sync comes from the makerspace where we have different people with different levels of understanding using the machines. I've seen people manually twist one of the Z screws on the TAZ, thinking it would lift the X axis boom. Wiring problems can also cause the motors to get out of sync. Having kids around the printer often causes things to get outby the_digital_dentist - Mechanics
This page has photos of my own custom built approximately 30x30x30 cm printer, MegaMax. Print quality is pretty good now (see the photos of the snakebite extruder parts on the above linked page, and my thingiverse items here: http://www.thingiverse.com/search/page:1?q=digital_dentist&sa=), but I can still find flaws in the prints that I attribute to slop in the drive/positioning mechanism.by the_digital_dentist - Mechanics
The linear guides have arrived and are smooth as butter! Getting ready to mount them later today... I'm going to try printing the standoffs that connect the bearing blocks to the undercarriage. If that doesn't work well I may have to mill some from aluminum. Fingers crossed!by the_digital_dentist - Mechanics
Very tiny. Everything that causes the extruder to deviate from the gcode path in the XY plane will have a visible effect in the print. Even vertical errors will be visible because the plastic line being laid down will vary in width. The prints we make can still be functional and aesthetically pleasing even with the errors- that is why there are so many machines using laser cut plywood in the sby the_digital_dentist - Mechanics
Looks like a great printer! Much more presentable than MegaMax. What temperature do you run inside the cabinet when printing ABS? Is all the heat provided by the print bed and the motors or do you have an additional heater? I normally run my printer inside a thermal enclosure (http://www.thingiverse.com/thing:269586), letting the print bed heater provide all the heat. It takes about 5 minuteby the_digital_dentist - Mechanics
Right now I'm running the motors off the 12V supply. I am considering switching to 24V. What is your experience with running the higher voltage on the motors?by the_digital_dentist - Mechanics
QuoteGarry Bartsch Sorry I can't comment on the vibration but that's a wicked looking Heavy Metal printer. How's it's print quality? It's pretty good, but I am always striving to make it better. More photos of the printer and some recent prints for the SnakeBite extruder here: https://drive.google.com/drive/#folders/0BxckS0Y4E9lzN1hlOGtaeUdZcUU QuoteA2 It looks to me like the idler belt pullby the_digital_dentist - Mechanics
Quotecozmicray jaguarking11 Point taken -- you sound like an electrical engineer Please comment on the use of a 120V AC heated bed on a 3D printer since the expert, the_digital_dentist, has stated that it isn't a good idea? Thanks Before I was a dentist I was an electrical engineer for 22 years. I can state unequivocally that low voltage is safer than high voltage. Comparing commercial prby the_digital_dentist - Mechanics
Connecting 110V to the printer isn't a good idea because of potential safety problems. In order to be safe you'd have to connect through a transformer, but if you';re going to do that, you may as well use a lower, safer voltage. Glass plates are fine for unheated beds, but glass is a poor conductor of heat and you'll end up with hot and cold spots. Some people use an aluminum bed to spread theby the_digital_dentist - Mechanics
I just ordered some 9mm wide GT2 belt and pulleys from Folger and will give that a try to see if it helps either the vibration problem or print quality. The pulleys are for 5mm shafts so I'll have to bore them out to 1/4", but that will be quick and easy. I am now preparing to try a ball screw drive instead of the belt. I pulled a ball screw assembly from a scrapped industrial machine and madeby the_digital_dentist - Mechanics
My printer has 12"x12.5"x 1/4" cast aluminum tooling plate bed riding on and aluminum undercarriage with 4x Thompson Super 8 ball bushings and 1/2" guide rails. The bed is moved by a NEMA-23 stepper with a 5mm pitch, steel core, urethane drive belt and matching pulley. When printing at low speeds the whole thing vibrates and makes noise. If I disable the motor current and push it by hand I getby the_digital_dentist - Mechanics
You know it is possible/easy to print with ABS on unheated PIR foam. I have done it- see As you can see, it sticks quite well! I got the idea from an industrial Stratasys 3D printer that prints on expensive polyurethane foam blocks. No, the bottom surface won't be as smooth as it would on a glass or aluminum bed, but most of the time that smooth bottom surface isn't needed. The Strataby the_digital_dentist - Mechanics
Hmmm. You're talking about casting a plate. Then you have to finish it. I would consider the time, effort, tools, and materials all that would take, and the low probability of success, and then ask myself what is my time/labor worth and is that really the sort of problem I want to devote my energy to. For me, no. Maybe you have different priorities. You could buy rod stock and a tap and dieby the_digital_dentist - Mechanics
Don't the screws transfer the motor vibration to the frame?by the_digital_dentist - Mechanics
I have a ginormous printer that uses NEMA 23 motors and is too loud. Did you ever get an order together for some of the dampers for NEMA 23s?by the_digital_dentist - For Sale
John, It sounds like the autoleveling scheme is actually much better and more useful than I would have thought. When I built my machine I went for maximum rigidity and used 1.5" 8020 for the frame. For an example of the result, I recently threw the machine (OK, I set it down gently) in the back of a pickup truck, drove it to the Milwaukee Maker Faire, turned it on and started printing withoutby the_digital_dentist - Mechanics
As I understand it, this "bed leveling" technique will result in all layers being skewed in the Z-axis by the amount of the error in the physical level of the bed. It seems to me you're trading a relatively small problem for another small problem with a lot of complexity thrown in for fun. To use your example, if the far side of the bed is 1mm higher than the near side, your print of a cube wilby the_digital_dentist - Mechanics