Picking the perfect stepper motor is more complex than just inductance/resistance/max current. Unfortunately few of us have the resource to buy many motors and look at resolution of motion. I hope to do some basic steps once I've got rid of some comparatively noddy problems on my test bed machine. Edit: Here are some tests I ran in the past. I'm nearly ready to run those tests on my own machinesby WesBrooks - General
In the vibration section: "2-Phase stepper motors can only miss steps in groups of four. If you are missing steps in multiples of four, the vibration is causing a loss of synchronism, or the load is too great. If the missed steps are not a multiple of four, there's a good chance the wrong number of pulses or electrical noise is causing the problems."by WesBrooks - General
Firstly a disclaimer: I don't think this damages the machine but can't be sure. Do at your own risk! Power up a machine and make sure the motors are not in an idle power level. Grab one of the steppers and rotate it (over torque) it on one direction while it is still. Note the step size. I't quite chunky! More than you'd expect from one physical step, and one micro step would be more or less impby WesBrooks - General
The polymer bearing are becoming popular with bed slingers. I've got them on my recently built P3Steel, but will most likely get them on my redesigned Ormerods if I can get past some wobbly issues!by WesBrooks - Fisher
There's normally some tie between - and ground to reduce noise and dump AC voltage to ground. I could see an issue where tying multiple units in series could push the capacitors out of there voltage spec. That said, I imagine they are speced to dump mains AC voltages.by WesBrooks - General
Try to find out all you can about the stepper motors you have. A full specification sheet with inductance and rated current would be perfect. Without that you may need to start low on current settings and slowly raise them until you get the performance you want, or they get warm to the touch. There's enough peope on here that will pitch in with board recomendations but bare in mind with ramps foby WesBrooks - General
I've been looking at this recently. If you apply a sufficient torque to a stepper motor (or ask it to accelerate or rotate at an excessive rate) it doesn't skip by 1 step at a time, it skips by 4. I'm talking physical steps here too, not microsteps. So when the motor is commanded to start instantaneously what is actually happening is it is being asked to accelerate from 0 to speed before it lagby WesBrooks - General
Ultimaker's CE Certificate (https://ultimaker.com/download/72576/Sum-prt-00117111315451.pdf) is interesting as it mentions the machinery directive and also has a certificate authorising unattended operation. CE Certificate: Unattended Operation: The unattended operation certificate is interesting as it doesn't seem to list anything formal that the CE certificate doesn't list other than "NL401by WesBrooks - General
Scrub that, MakebotsCE certificates on this page are more thorough: The main safety one appears to be: QuoteBSIGroupBS EN 60950-1:2006+A2:2013 Information technology equipment. SafetyGeneral requirements specifies requirements intended to reduce risks of fire, electric shock or injury for the OPERATOR and layman who may come into contact with the equipment and, where specifically stated, forby WesBrooks - General
Ok, for the pre-built machines the most complete set of regulations that I have found is from Stratsys (Brochure on: - ) and is as follows (copied word for word - including repeat of FCC): CE (low-voltage and EMC directive), FCC, EAC, cTUVus, FCC, KC, RoHs, WEEE, Reach Of those for a UK machine I think the following are most relevant: CE (low-voltage and EMC directive), RoHs, WEEE, Reach. Wiby WesBrooks - General
Yes I would be looking at drag chains, making sure the bend radius of the chain was larger than the bend radius of the cable spec. I'll have another look for cable life specs as I guess stating when cables should be replaced woild be a good thing to do.by WesBrooks - General
Thanks for the comments. @dc42 Kind of answered my question posed on the duet forums here. I had been wondering if twisted pair for the main cable run and grounding the motors would be enough for EMC emissions as the case should act as a cage catching the emissions from the coils themselves. I thought perhaps the shielding grounded at the ormerod 2 case was mainly acting as a ground for the stepby WesBrooks - General
Found a good discussion here with directives listed. I will now go looking for the certificate of incorporation for the duet boards.by WesBrooks - General
Any summaries available for the regulatory requirements that have to be met to supply a printer as either a complete kit or prebuilt printer?by WesBrooks - General
Hi all, What is recommended for flexible, shielded stepper motor cable? Got two applications in mind, one upto 2A and the other 3A motor current limits. Thanks.by WesBrooks - General
Yes thanks, I'm aware the newer boards are nicer, and I am keen to see the progression of the multithread (or multiprocess) capabilities such as simulation of non-active jobs during print. Also really not a fan of the naff hot end connectors on the v0.8.5 and even less so the doubled up header pins on the 0.6. I've got some resolution test cases that I discussed on the duet forums an age ago thaby WesBrooks - Ormerod
QuoteVDX And beside -- in the first years we received some "notes" from them to avoid the mention of "FDM" with our extruders ... so we found the synonym "FFF" for "FreeFormFabricator" instead I thought that was Fused Filament Fabrication?by WesBrooks - General
Other mods: Ditched acrylic end plates in favour of printed parts mounted onto 2020 extrusion that mounts onto original y axis extrusion. Screws in y axis rod supports, screwing axially onto rods to ensure belt tension doesn't pull sides in. Microswitch x-axis limit. Rotated x axis belt 90 degrees about x axis and run half of it in extrusion. Used x axis smooth rod on z axis. Dropped y axis beltby WesBrooks - Ormerod
Update! This is the first major itteration but it is definately draft, and bits to mount extruder is a bodge. Only design things that remain from the Ormerod 2 is the plates that make the bed support, and the extruder. It reuses the smooth rods, extrusion, bed support, extruder, and bearings. Major changes are: GT2 Belts Belt driven z 4:1 Reduction belt drive on z. Belt tension done on idlerby WesBrooks - Ormerod
Go simple - thermal switch or resettable thermal fuse that is open over 50C. Solenoid that unlocks when energised. No need for any software then, and locked in a power cut. Just ensure that tools are needed to override the interlock if needed, rather than an override being available with no tools. Edit: I was thinking this should be on the bed but could be on the hot end too.by WesBrooks - Safety & Best Practices
System now running with a 20A fuse and a 30A MOSFET from a 25A power supply through 14awg silicone insulated wire. All seems fine and completed a few autotune cycles with no issue. Build trials next week and I'll try to figure out a 20A+ thermal snap switch for 130C ish. Doubt all would have been fine if I'd built the kit with the sub 14awg wire, no fuse or mosfet.by WesBrooks - General
Hi, Can anyone point me toward a guide for setting up a four point bed level correction in the firmware? Thanks.by WesBrooks - Firmware - Marlin
I've probably got a few spare second hand ones and RepRapLtd are worth a shot.by WesBrooks - Ormerod
QuoteMKSA M8, M10, M12 are not really necessary here but if you are in cars, bikes etc OK Fair enough on M10 & 12, but M8 threaded rod is common on the Mendel etc. Not sure what size the threaded rod is on the base of the Prusa mk2.by WesBrooks - General
Depends on what threads you are cutting, and on what material. External or internal? Blind or through holes? Material? Just de-burring after cutting threaded rod? Cleaning threads? To be fair I'm no expert but those are the questions others may need answering to guide you to the best choice. For working with most RepRap style machines I would imagine you want an ISO tap and die set at least coveby WesBrooks - General
Yeah, big margin of error, but the other plate I have measures near double the resistance. I expect this is an aliexpress style job. Manufacturer isn't obvious.by WesBrooks - General
Hi, Had many troubles with a kit I purchased early december. This is a P3Steel based kit with RAMPs. Just soldered the 14awg heatbed wires on and checked resistance. I'm only seeing 0.7Ohm? I thought this was a short but nothing visible and no shorts to the aluminium. Checked the expected load and wattage and it is neatly 200W (allowing for errors) and would draw 17A. The neatness to 200W leavesby WesBrooks - General
Some interesting ideas there! I'm considering a belt z-axis as the trapizoidal screw hasn't quite got shot of all of the z wobble. Will have another search on the ormerod forum for z-wobble first.by WesBrooks - Ormerod
Sorry I should be clear that I can't buy on behalf of the makerspace so will need to relay this information bavk to them before I can confirm. If you're more than 100 miles or so from us then it would meed posting, but breaking it down wouldn't be an issue.by WesBrooks - For Sale
I've just rebuilt an Ormerod for a Makerspace in Liverpool, and they are currently running on a board loaned from me, and don't have the IR sensor or metal arm. What county are you from? I know these kits were north of £450 new, but alas aren't holding value in the face of the new duets and rigid mendel 90s/prusas/knockoffs and super cheap current entry level kits. I paid 80 on ebay for one withby WesBrooks - For Sale