Yes, the ATX isn't ideal - the 12V output isn't at all well regulated. The bed takes approx. 10A, extruder 4A and the steppers add a couple more Amps typically. The 12V rail will quite happily provide all this current - and plenty more, but the volts will continue to drop. I think the low cost of the ATX is the reason it's bundled with Ormorod which is an exercise in low cost product design. In pby Radian - Ormerod
dc42 - your brain has been in overdrive making great improvements to Ormorod so we'll let you off I haven't followed any other discussions relating to the "heat spreader" but, at first blush, it seems like a small enhancement that may well be optional. I'm still digging around for prior knowledge on the topic - I'd hoped to find FLIR type images of with & without etc. but no luck so far. Eby Radian - Ormerod
Is everyone happy with the silk screen/solder resist being the only insulator between the heat spreader and the copper traces on the PCB? No doubt it has enough insulation resistance at only 12VDC (so long as it's in good condition). However, with no back EMF suppression we get 50V transients appearing across the heater. I'm not so sure how this might affect things long-term. Another good reasonby Radian - Ormerod
I just downloaded iamburny's Slic3r settings and it puts up an info box saying that Support material was improved since the last version and it recommends restoring to the default settings although it doesn't mention how to. The version I have is 1.0.0RC2 which looks like an increment since December. The only parameters for support material appear to be Pattern spacing (2.5mm) and Raft layers (0)by Radian - Ormerod
There's a handy RepRapWiki article on Lubricationby Radian - Ormerod
Hi Dave. For my laser I currently use LinuxCNC which comes as a special distro claimed to be based on a real-time version of Linux. I have no idea what worst-case latency to expect with Raspbian but I've seen reports of 10ms which would be an issue. ARM assembler is my favorite too I started on the very first generation (when the A in ARM stood for Acorn). I recently tried out the Acorn RiscOS rby Radian - Ormerod
Interesting. I see each board is managed by a PIC24FJ64GA106 which can be re-programmed. The Pi GPIO appears to be passed thru on the shrouded headers so additional IO for heater control, endstops etc. would be available. Of course it would also require the appropriate RPi software to convert gcodes to stepper drive signals. I've been searching around for something similar to run the motors in mby Radian - Ormerod
Quotedc42 The mirror is an interesting idea, especially as I print PLA direct on glass, so there is no Kapton to get in the way. I see plenty of people that swear by this. If nothing else it seems to ensure a better surface uniformity as the glass is chosen for minimal distortion. Ambient IR would be my only concern as it would ping around from all over the place, but your relative measurement sby Radian - Ormerod
OK, so we probably all know this but it's worth spelling out: The reason it's so persnickety is that It's a square law thing because Power=I*I*R. So with a fixed heater resistance of 1R: Vsupply => Power in bed @10V => 100W @11V => 121W @12V => 144W @13V => 169W ...and of course @14.14V => 200W With a 9.16% drop in voltage from 12V to 11V the power in the bed drops by 16%by Radian - Ormerod
We've been trapped in this loop for a while now. Even El~Cheapo ATX supplies are fine for Ormorod's motors and feed to the 5V regulator but the 12V just doesn't quite it for the heated bed element. I think the hot end is quite usable as well.. If the heated bed PCB design was tweaked to perform at 10V most of us would be happy bunnies.by Radian - Ormerod
QuoteMickyblueeyes I haven't looked at the schematic for the power here but if it was just powering the heater then a simple transformer rectifier supply would suffice, the caps have no purpose in a heating circuit, a simple heatsink with a meaty rectifier would mean no fan requirement and high reliability. Oh yes, if it was just the heaters and the +12V connections to these were separated fromby Radian - Ormerod
Hi Dave, those things can be fun (if you REALLY know what you're doing!) I don't think it will work too well as you describe it though - the 15A draw with the heaters on alone will deplete 1000uF way before the next half cycle of 50/60Hz AC. (around 1ms) 20,000uF as a minimum I'd think. Also it would be in desperate need of a current limiter to prevent any unintentional Arc Welding. Managing surby Radian - Ormerod
Hi, Nil Einne - very interesting to read your take on this. It makes me wish I'd gotten into 3D printing from the beginning. I'm usually in on new technologies from the start but in this area I have so much catching-up to do. I think when I first saw Ormorod, it looked like something I could see sitting on the bench without being a massive curiosity like most of the other systems I'd seen up untiby Radian - Ormerod
Just to add to the advice about using paper, I place a clean sheet of copy paper (as iamburny points out, conveniently 0.1mm thick) and adjust Z until the paper is just grabbed. It's very tactile, there's a slight feeling of buzz as the vibration from the fan modulates the grip - you soon know when it's just at the right height. I also do this with the nozzle at 200'C to clear any filament away fby Radian - Ormerod
Thanks for the explanation Ian - I really ought to read all the Slic3r documentation to see what other hidden Gems there areby Radian - Ormerod
Nothing special, 0.24mm stock settings supplied by RRP for Ormorod-0.5 (i.e. 1mm retraction only) I really only wanted a quick print to see how the 40mm unsupported overhangs would work out. I haven't been able to decompose the G codes but I can only guess the design compensates for droop by flattening subsequent layers above the overhang to fill any gaps. I'm new to 3D printing so I assumed yoby Radian - Ormerod
Well it was just a musing. Still, there's a healthy hinterland where hobbyists do business on ebay selling quality built clones of things (e.g. stepsticks). Ebay reputation is one example of a loosely coupled quality control system that might be adequate. Whatever, I think sub-£1000 3D printing will remain a niche business until the big names see it as being a truly commercial proposition with maby Radian - Ormerod
I printed This Thing to see how Ormorod would cope with printing the deck with no support. Hang the 45' overhang rule, this thing spans 40mm in mid air! View from below (wheels and carriers were printed separately) Deck looks pretty flat from above: How the heck did it manage that !?!?by Radian - Ormerod
Quotedmould Yes, 3D printing is really great and all, but it is definitely not (yet) suitable for any sort of mass production. Apart from the time, there is zero economy of scale and quality control is more problematic. As demand increases, I feel that RepRapPro will have to abandon the idea of printing, even though it might go somewhat against their ideals - you eventually find it a lot betterby Radian - Ormerod
In another topic: Quotedmould Yes, 3D printing is really great and all, but it is definitely not (yet) suitable for any sort of mass production. Apart from the time, there is zero economy of scale and quality control is more problematic. As demand increases, I feel that RepRapPro will have to abandon the idea of printing, even though it might go somewhat against their ideals - you eventuallyby Radian - Ormerod
All four of my motors had some degree of degradation on the terminal pins. One (kindly replaced by Ian) had a pin totally missing - melted down to a perfect little blob actually. I can only assume the motor inspection/test involved pulling a live connector off with plenty of volts trying to keep the circuit closed. Anyway, another one of the other motors had lost the plating on the same pin and wby Radian - Ormerod
Hi Rory, in keeping with your findings, the 3V3 appears to be regulated independently in most ATX designs. I'm not encouraging anyone to open up the PSU unless they know exactly what they're doing so I've been restricting myself to probing around on the outside. To my way of thinking external corrections are the only ones really worth considering. The 12V system on the Alpine does at least appearby Radian - Ormerod
Naturally there are differening opinions about what constitutes an acceptable "fix" - if indeed there's anything that needs fixing. In my opinion RRP have a clear and sensible objective to provide a safe, simple and certified power source at the lowest cost possible. The ATX is so close. In order to maintain the object and to avoid any health & safety issues I think we should only contemplateby Radian - Ormerod
I was wondering about the different types of glass out there - opaque white glass for instance. Also, frosted glass - might that improve adhesion?by Radian - Ormerod
Hi T3P3, In your blog post it says of the transient: "This noise is relatively local to the MOSFET though, at the 12V input connector it is down to 750mV pp." While it's true that there's only a small transient on the 12V rail probably due to parasitics and the recover of the PSU, a transient of 50V wrt ground is still present throughout the Bed and connecting ribbon cable at a high dV/dt. Giveby Radian - Ormerod
Glad you found the problem. I'm sure support at reprappro dot com would help you with the wonky thermistorby Radian - Ormerod
dieterzar, I think you're probably close to the truth about the "mixing" of rails in the feedback path of these supplies. Every manufacturer I've seen appears to use the same trick, otherwise separate transformer primaries and choppers would be required. dc, don't forget the heatsinks for those LEDs! A few seconds at 1000mA and it will start to fade before your very eyes (not that you should'ntby Radian - Ormerod
OK, so I just pulled the case of a PC with some random cheap looking ATX PSU and dumped a 12V/50W halogen on a spare 5V drive plug. The 12V went up by 0.25V! This is interesting. The lamp is pulling around 2.5A, hence 12.5 Watts. If it's a linearly proportional effect then we need to dump four times as much to restore our missing Volt. An additional 50 Watts is nothing to the PSU, but somethingby Radian - Ormerod
Quotebobc Although the ATX PSU has a lot of benefits, one of the things they are not so good at is dumping loads of amps onto a 12V rail. Hi bobc, from what I've see by googling around for ATX PSU schematics I think that few (if any) have closed-loop regulation on the 12V rails because I haven't found one yet. But even a cheap one like the Alpine can deliver tens of Amps, albeit with a lost Volby Radian - Ormerod
Sad to hear that dmould - such an easy mistake to make. Given the proximity of +12V to the thermistor input going direct to a micrcontroller pin, a shrouded header would have been far more sensible. Easier for the contract manufacturer to assemble as well.by Radian - Ormerod