Show all posts by user
Discuss any sort of mechanical stuff here: positioning systems, gears, extruding methods, etc.
Re: PIC Extruder Firmware and communication errors - 15 years ago
I've finally solved it! after bread boarding an extruder and power & comms board with no components in common and still having the same errors. It was the power supply, I don't know why it only effected the extruder but there was a 600mv ripple at 145kHz on the power line even after the filter caps and the 7805.by peteredworthy - RepRap Host
PIC Extruder Firmware and communication errors - 15 years ago
I'm finally getting there. I have working X,Y,Z Bot, thanks to Bits from Bytes and the RepRap Research Foundation, but I just can't seem to get the extruder board/firmware to work. If the extruder board is included in the comms chain then the v1.0 reprap host software outputs 'sendMessage error - retrying' repeatedly. I've tried; - linking only the extruder board and the I/O board - flashing tby peteredworthy - RepRap Host
Re: Stepper Motor Driver v1.2 in the UK - 15 years ago
The files necessary to make the boards are in the SVN so you could create your own boards, for example; using a laser printer and toner transfer to mask the board for etching. The parts finder should have references to UK locations for the components, but I've not used it in quite a while and only for the PIC electronics. In the end I used boards from RRRF and components from Farnell All thatby peteredworthy - Controllers
Re: Tool-head controller - 15 years ago
A few thoughts I had about the head interface requirements were: Hot Plugging - If we are going to have automated head swapping then some form of bus isolation or hot plugging will be needed. RS-485 transceivers that support hot plugging are available. For other buses a combination of an enable line for the tool and bus isolators would be needed to ensure power on transients didn't cause problby peteredworthy - Controllers
Re: EMC based reprap working and printing but I need programming help! - 15 years ago
You don't say what platform you are using, but I'm going to guess some flavour of Linux for EMC. The following command will do what you are after, (fileIn and fileOut will need replacing with real file names) sed -e 's/^101/M8/' -e 's/^103/M9/' -e 's/^104.*$//' -e 's/^105.*$//' -e '/^$/ d' fileIn > fileOut If you need to convert other commands just add an extra, (XXX is the command to replacby peteredworthy - Reprappers
Re: Stepper motor cant go fast - 15 years ago
Actually thinking about it a bit more, reversing one diode would pull that pin to gnd or 12v and reversing two would look like a short. So even less helpful than I imagined ;-} The complete drop to 0v when the bridge is 'off' is very odd, I think nophead's line of reasoning was if the current isn't going through the sense resistor where is it going? Does the L297 control the two bridges separatby peteredworthy - Controllers
Re: Stepper motor cant go fast - 15 years ago
Sorry if this is too much like 'is it plugged in' type advice. The diodes being the wrong way around would look the same as them not being there. A basic test of the orientation would be that all the non-stripped ends of D1->D4 should be connected to earth and the striped ends of D5->D8 should be connected to 12V. If that doesn't show try checking if pin 1 is connected to the striped endby peteredworthy - Controllers
Re: www.Reprap-Models.com - 15 years ago
For licensing the models, which I think you are alluding to with 'set of rules', could I suggest using an existing license/collection of licenses. I've always liked the Creative Commons licenses as they provide a range of 'openness' that better fits reality than the all or nothing style of most licenses. I'm fairly sure that all of the Creative Commons licenses allow unrestricted non-commercialby peteredworthy - General
Re: Tissue engineering molds - 15 years ago
Gene Hacker, are you viewing the site from a university connection? It could be that the university has made some arrangement with Wiley.by peteredworthy - Tissue Engineering
Re: Augers - 15 years ago
That might work, although you would need to seal off the bearing/shaft from the screw part and of cause blunted the edges so it doesn't cut into the tube. Filling the thread with metal epoxy or similar for the last inch would probably be enough to stop leakage, assuming the clearance between the drill and the tube was small enough. Filling the thread reminded me of an idea. The thread could beby peteredworthy - Mechanics
Re: Augers - 15 years ago
I've had a bit of a play with using standard wood cutting auger bits. I've not posted about it before as it was all a little haphazard and then got put on a back burner when the BfB kit arrived. In case it's of any use here's what I tried: I used 15mm bits inside 15mm (1/2 inch) copper tube, the same stuff used for cold water plumbing. I only tried PLA, as it saved having to deal with a heater.by peteredworthy - Mechanics
Re: Just how easily should the axes move... - 15 years ago
> "It is absolutely critical to have this distance accurate to within 0.5mm, otherwise you will have to re-do it later on" Where there are dimensions they tend to have +/-0.Nmm after them. I found for the longer distances, such as the diagonals, a tolerance of 0.2mm was very hard to achieve. In fact as I don't know anyone who has a 600+mm caliper, I can't really be sure I did. What I couldby peteredworthy - Mechanics
Re: Using digital caliper for positioning? - 15 years ago
While they may not be suitable for closed loop control it seems worth having a quick think about other applications. A couple I can think of are: - Non-linearity mapping, finding places where a one step is shorter or larger than usual This information could then be used to add or remove compensating steps to keep the absolute error to within half a step. This may not be needed, I don't know howby peteredworthy - Mechanics
Re: Windows Installer - 16 years ago
Excellent xsainnz, I've been looking at IzPack meaning to get together an installer for a while now. Could you post the install config XML? I'd like to get it working for OSX and standing on the shoulders of giants seems a sensible start ;-}> For those with SVN write access, IzPack can be integrated into an ant build script so we could have a target that auto-magically produced the installerby peteredworthy - RepRap Host
Re: RepRap near future - 16 years ago
I've thrown together a somewhat prescriptive page It is far from complete, but I think it's quite easy to follow what is needed from it. I've mostly been comming from the building angle so there isn't anything about software versions. Steve: I don't see why linux would be the prefered environment for the easy route or is it root ;-}by peteredworthy - General
Re: Laser Cut Parts (Bits from Bytes) - 16 years ago
Congratulations, Do you have a photo?by peteredworthy - Mechanics
Re: Filament - 16 years ago
Possibly a crazy idea but; as we are interested in measuring volume could we measure displacement? I'm not sure what liquid would be good to use, several of the plastics need to maintain a low moisture content so water isn't an option. I'm also thinking that creating a good seal would be quite hard, hence the 'bath' idea.by peteredworthy - Reprappers
Re: Request: Control via Internet - 16 years ago
Given the magic that already gets done by third world mechanics; It could be an opportunity to speed the introduction of higher tech development which typically has very high capital outlay costs. It could also sit there being ignored by the world. > Almost all people throughout history thought almost all ideas were "useless" until they were proven otherwise. I think history mostly tells us tby peteredworthy - Controllers
Re: I got steppers...I need help adjusting the current on the SMC board - 16 years ago
There are three separate inputs to the L297 (for current limiting), one from between R1 and one of the stepper motor's coils, one from between R2 and stepper motor's other coil and one from the potential divider formed by R3 and R7. The L297 controls the current through a coil by rapidly turning it off and on to keep the Voltage from its sense resistor below the reference voltage created by R3 aby peteredworthy - Controllers
Re: I got steppers...I need help adjusting the current on the SMC board - 16 years ago
Your calculating the voltage at the sense point correctly, but it's highly unlikely that your sense resistor is 2.7k. As your maths showed that would need 2.7kV to drive one amp through it, not to mention give off 2.7KW of heat ;-}> Assuming a 0.5 Ohm sense resistor 1A = 0.5V, with the sense resistors generating 0.5W of heat.by peteredworthy - Controllers
Re: OSX 10.5: Exception in thread "AWT-EventQueue-0" java.lang.NoClassDefFoundError: javax/swing/GroupLayout$Group - 16 years ago
This sounds very similar to: Where JDK1.5 seems to be being used independent of the JDK set in the Java Preferences.by peteredworthy - RepRap Host
Re: OSX 10.5 Software startup issues - 16 years ago
I'm not sure but it seems like Java 6 isn't being used to run RepRap on your system, even when 'Java Preferences' are set to jdk1.6. AFAIK all the 'Java Preference' tool does is change a link, /Library/Java/Home, to point to a different version's install location. This only works if the /Library path is used everywhere, anything that uses a path to a specific JDK won't be effected by the link chaby peteredworthy - RepRap Host
Re: FTIStrap - a RepStrap built from FischerTechnik parts - 16 years ago
The glue does seem to work particularly well. The translucency is also better than I have seen in examples made of HDPE. What is the strength like? In trying to find out what glue sticks are made from I've discovered that there is no single recipe; Ethylene-vinyl acetate EVA seems to be used a lot, but on it's own it is like rubber. Do you have any idea what the sticks you are using are made frby peteredworthy - Reprappers
Re: thermistor/thermocouple for BfB extruder with PIC electronics? - 16 years ago
For myself, I'd only heard of thermistors and thermocouples. A bit of reading wikipedia later.... Resistance temperature detectors (RTD) / platinum resistance thermometers (PRTs) seem like a great solution: - linear resistance change with temp - No isothermal blocks (not that the current design uses them) - No precision amps / signal conditioners needed - Wide temperature range From what I'vby peteredworthy - General
Re: thermistor/thermocouple for BfB extruder with PIC electronics? - 16 years ago
I've also got PIC electronics and a BfB extruder, what I've done is embed a 100k thermistor and a K type thermocouple in there. I'm planning on using polymorph and relatively low temps initially. If/when I move to ABS or something similar I'll move over to using Gen 2 stuff and the thermocouple. I was worried about the curing process, where the barrel gets heated to temperatures way above what tby peteredworthy - General
Re: Laser Cut Parts (Bits from Bytes) - 16 years ago
spcmicro: That looks a lot simpler for getting alignment right, but how do you judge the 'tightness' of the bolts?by peteredworthy - Mechanics
Re: Laser Cut Parts (Bits from Bytes) - 16 years ago
I found while assembling the corner blocks that measuring the distances between the two plates allowed for getting the bolts tight but not breaking anything.'generally' the plates could be pulled down to 7.7mm without harm, but I'm being a bit cautious and have mine a 7.8mm at the moment. (8mm would be the gap size with no flex, as that's the diameter of the rods). >Most cordless drills comeby peteredworthy - Mechanics
Re: 45 Degree Overhangs - 16 years ago
6) The shape may be printed more than one way up.by peteredworthy - Plastic Extruder Working Group
Re: New user, several new ideas. - 16 years ago
I'd say for most of the ideas the summary answer is 'Yes, it's more complex than that but we are working on it.' ;-} I have a few thoughts about creating a shape as a data storage medium. The register article's claims seem very dodgy. 450Gb on a sheet of A4 would require storing 7KB per square mm! which is about 35Gb/in2. That's about the same as turn of the millennium hard-drives. I don't thby peteredworthy - Mechanics
Re: Conducting trays in elastic materials - 16 years ago
Just to check I understand the suggestion: The conductor would remain in a liquid state. If so how would we ensure that the joint between the components wires/legs/etc and the tray are sealed? It seems unlikely that we could fab an interference fit at the moment. Could the component be placed during building and then the seal extruded to it? If the components were already placed some extra entrby peteredworthy - Plastic Extruder Working Group