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People building or using RepRaps.
Re: Which Kit? Railcore? SecKit? Other? - 22 days ago
You won't need training on a lathe to build a UMMD copy. It's not entirely necessary to use a milling machine, either, though it can be very useful. Simple cuts and accurate, square drilling are the main uses for the mill- square up the ends and matching lengths of the frame pieces so that they bolt together squarely, and milling the perimeter of bed plate. You will want to drill holes squarely iby the_digital_dentist - CoreXY Machines
Re: Inconsistent Z axis steps/mm - 27 days ago
Are you letting the bed heat up before you start the prints? Your controller may report the target temperature is reached long before the bed actually stabilizes. Can you post a picture of the printer?by the_digital_dentist - General
Re: Inconsistent Z axis steps/mm - 28 days ago
Are you using PID control on the bed temperature? Do both screws lift the same amount or does the bed tilt when you run these tests? Pictures of prints might be useful here.by the_digital_dentist - General
Re: Inconsistent Z axis steps/mm - 28 days ago
What are the acceleration and jerk values for the Z axis? If you're trying to make it do things too fast the motors might skip steps.by the_digital_dentist - General
Re: VFA (vertical fine artefacts) - 6 weeks ago
That one is Son of MegaMax (SoM) not UMMD. UMMD has the electronics enclosure at the top of the printer. That helps keep most cables short because the XY stage is also near the top of the printer. It is also easier to service/modify/maintain because I don't have to crawl on the floor to access the critical stuff. I had considered making the XY stage/electronics a drop-in module so I could use diby the_digital_dentist - Printing
Re: CoreXY X axis wobble - 7 weeks ago
Here's the new post on this topic:by the_digital_dentist - CoreXY Machines
Re: Issue with NEMA 17 Stepper Motors and DRV8825 Drivers during Homing - 7 weeks ago
Check jerk and acceleration settings. If either is too high the motors can miss steps. Also keep in mind using 0.9 degree motors requires 2x the step rate from the driver (compared to 1.8 degree steppers) to achieve the same speed. Watch the temperature of the driver chips. They can overheat easily if you're using tiny modules because the PCB is too small to dissipate much heat. When a driver ovby the_digital_dentist - General
Re: 4 months in 6 minutes - 2 months ago
Looks like a quality build, as usual!by the_digital_dentist - Developers
Re: Microstepping driver DR8825 - 2 months ago
DRV8825 drivers have long been known to create print surface quality problems. There is something called a TL Smoother that fixes it. Or you could use a different driver that doesn't have that problem. See:by the_digital_dentist - General
CoreXY X axis wobble - 2 months ago
A while back I noticed the X axis wobbling a bit in my corexy sand table as the magnet carriage moved back and forth on the X axis (Y position fixed). I decided to check my printer, UMMD, to see if it had the same issue. It did. The data indicated that the period of the wobble was 40 mm which corresponded to the distance the carriage moves with each rev of the drive pulleys (20 teeth, 2mm pitch).by the_digital_dentist - CoreXY Machines
Re: Is it okay to not to use smooth rods in 3d printer - 3 months ago
You can use spaghetti if you want. Just don't expect much. Ball bearings will cut grooves into soft steel or aluminum. If you can't get hardened and polished rods, it would be better to use bronze or UHMW bushings. UHMW is cheaper and will last longer than PTFE in a sliding bearing situation.by the_digital_dentist - Reprappers
Re: Z-Axis thread rod pitch ? - 3 months ago
Yes. That's why they're called "lead screws", not "pitch screws".by the_digital_dentist - Mechanics
Re: Z-Axis thread rod pitch ? - 3 months ago
What I was trying to say was that the 8mm pitch number you saw was not actually pitch, but 8mm lead with 1.25 mm pitch.by the_digital_dentist - Mechanics
Re: Z-Axis thread rod pitch ? - 3 months ago
Thread pitch is the spacing between adjacent threads on the screw. Lead is the distance the nut will travel in one rev of the screw. With single-start screws, pitch = lead. With 2 start screws, lead = 2x pitch, etc. You can tell how many starts a screw has by looking at the end of the screw and counting the notches.by the_digital_dentist - Mechanics
Re: Cartesian to CoreXY? Which one.... - 3 months ago
Here you go- modular, rigid CoreXY stage that can be dropped onto a Z axis mechanism: There are some updates, so search/follow the links. I went to optical endstops, shortened the extruder carriage, etc. I used 4040 t-slot, two pieces of cast tooling plate, and some 1.5 x 2" aluminum tubing. You can make all pulley and motor mounts from one piece of tubing. F608 skate wheel bearings are usedby the_digital_dentist - General
Re: German RepRap Protos V3 Firmware upates - 3 months ago
QuoteVDX ... yes, there are newer/better solutions with time ... but seems, there are enough of the "older" systems running smooth nd reliable still -- so depending on the individual circumstances You make a valid point, there are plenty of obsolete systems still working, but unfortunately, zurferjoe's isn't one of them. zurferjoe, from what you have described, in order to get it working agaiby the_digital_dentist - General
Re: German RepRap Protos V3 Firmware upates - 3 months ago
One of the problems with Arduino based controllers is the necessity of recompiling the firmware every time you want to make a change to the printer's configuration. Newer/better controllers have printer configuration in text files that get read each time the controller boots up, so all you need is a text editor to change the config file, then cycle power and your changes are applied. There are noby the_digital_dentist - General
Re: German RepRap Protos V3 Firmware upates - 3 months ago
That printer came out in 2015. In my distant past experience with Arduino stuff, updates to the Arduino IDE broke compatibility with old printer firmware. This was one of the things that motivated me to dump Arduino based controllers- I was tired of hunting for and trying to maintain old versions of the IDE so I could keep my printer running. You might be able to find a compatible version of theby the_digital_dentist - General
Re: Prnter wont print circles just ovals - 3 months ago
When you measure anything, there will be some error in the measurement. If you're measuring with a caliper, the error might be on the order of 0.1 mm depending on how you hold the caliper and the basic accuracy of the caliper itself. If you measure an actual 20mm object and there's 0.1 mm error, say 20.1 mm you'll correct for it by reducing steps/mm. That may get your 20mm object to read 20mm aftby the_digital_dentist - General
Re: Prnter wont print circles just ovals - 3 months ago
QuoteRoberts_Clif Your 3D Printer firmware steps need to be calibrated. On my 3D Printer it is this line "#define DEFAULT_AXIS_STEPS_PER_UNIT { 80, 80, 1600, 94.4962144 }" And calibrated below #define DEFAULT_AXIS_STEPS_PER_UNIT { 79.7, 79.7, 1594, 94.4962144 } THis is what I used to calibrate steps 79.7 steps/mm should not be correct unless your X and Y axes have some sort of planetarby the_digital_dentist - General
Re: Possibly building 3D printer - seek a bit of advice ... - 4 months ago
It would be worth a try, but I wouldn't count on it working for the Z axis. Those things are made to be cheap, not to provide accurate or precise positioning. That means the gears are probably not very well made and you'll see artifacts that repeat in the Z axis of prints every time the worm completes a rotation. The Rino I linked has very high quality gears and very fine adjustment for backlashby the_digital_dentist - General New Machines Topics
Re: Possibly building 3D printer - seek a bit of advice ... - 4 months ago
Guitar tuners don't have bearings on either gear because they are made to be adjusted a little at a time and then sit. I would also not expect the quality of the gears to be very high which will result in repetitive artifacts in prints. There's no substitute for quality gears. I tried to make a Z axis worm gear drive using some cheap gears I bought via ali-express. It was awful.. The Rino drive uby the_digital_dentist - General New Machines Topics
Tool for sanding disc brake pads - 4 months ago
My bike has belt drive and a continuously variable transmission. It's been extremely reliable, except that it also has hydraulic disc brakes. Those have been not so reliable. In fact, those brakes alone have required more maintenance than any whole bike I've ever owned. The biggest problem with disc brakes is that they squeal a lot. When they squeal, they don't stop the bike very well. Fixing tby the_digital_dentist - Look what I made!
Re: Possibly building 3D printer - seek a bit of advice ... - 4 months ago
If you're interested in building a tall printer, a belt lifted z axis can be made to work easily and probably more cheaply than if you use screws to do the lifting. A worm gear drive with a 30:1 (or more) drive ratio will stop the bed or XY stage from dropping when power is cut. See my UMMD design linked in my sig, below. I used a Rino that costs about $118 via ebay, but someone at the makerspaceby the_digital_dentist - General New Machines Topics
Re: Possibly building 3D printer - seek a bit of advice ... - 4 months ago
50 hours and $500 to design and build a high temperature 3D printer? and you want quality? and you want to print "heavy" objects? and you don't know how to set up firmware? and you don't have access to materials? It's going to take more than 50 hours just to select the parts/materials.by the_digital_dentist - General New Machines Topics
Re: Quality Parts - 5 months ago
I've had Gates LL2MR09 belts in my printer for at least 4 years without and problems.by the_digital_dentist - Mechanics
Re: Is this classed a rerap? - 5 months ago
I'd check steps/mm and microstep settings in the config files.by the_digital_dentist - General
Re: VFA (vertical fine artefacts) - 6 months ago
Have you seen this:by the_digital_dentist - Printing
Re: Z seam fix? - 6 months ago
Try the random seam location option instead of aligned. That will scatter the tiny bumps all over the print. Also you might try printing the outer perimeters first (default is inside first).by the_digital_dentist - Slic3r