Have you got any bookmarks to UV cured extrusions Andy ? I can see that if you had the viscosity right, then the tool head could UV cure as it goes.. very cool. I'm thinking expensive extrude material though... Grahamby grael - Controllers
Annirak, I missed your desired toolhead list at top. That explains it. I do think though, that rotary switch connections are a viable option, and then you could rotate the heads down, and lock them in place, all with servo motors. Graham.by grael - Controllers
Whoops... Yes, I should have written "Zach" there. sorry ! Graham.by grael - Controllers
I can't say I disagree with anything there Annirak, But, I do want a base machine that can handle the common tasks with ease, and have room for expansion. With what I'm planning, I think that most common extra tasks can be implemented with existing I/O, and tasks of your nature can be done by extension. The SATA cables sound like a good idea, however you may find that they don't have enough straby grael - Controllers
A lot has already been achieved with reprap, but yes, if you put it like that Forest ("core premise as being impractical"), then I have to agree. We(humans) are not technically advanced enough (yet) to be to making Von Neuman machines. As such, there is a decision to me made about how much of a reprap should be self build, and how much should be mass produced. I think the term used in relationby grael - Controllers
This thread seems to have run through the prickle bushes, but it raises some good points. I think that unless you are only printing other people's parts to get your enjoyment, then a builder needs to be unusually competent to be able to take advantage of the technology. Where the confusion creeps in, is that some of those unusually competent people are gifted with electronics and/or software asby grael - Controllers
My distributor must have given me the special "Introductory" dealby grael - Controllers
Annirak, I've had no experience with CAN bus, I know it's popular in the automotive field though, which would put it in a similiar environment, i.e. no more than a few meters maximum size, electrically noisy environment. I haven't researched CAN properly, but just spending a couple of minutes now to look at it, I have these points to note: ~It looks like CAN still needs external tranciever chipsby grael - Controllers
Hi Annirak, What do you want to put on the different tool heads ? If you look over on the "Beyond the Sanguino" thread, I have further info on the board I'm working on. I was thinking that the extruder could integrate an RGB+black+white mixer for coloured builds, and simply have each spool come in from an angle out from the vertical. So long as the pressure into the mixing zone doesn't allow baby grael - Controllers
I haven't programmed ARMs before, but I agree in general. However, the bigger ARM micros aren't much more expensive, and I'm planning a board based on ST's STM32F103VBT chip myself. More pins means the L297 aren't required, and then it's a small step to put the drivers on the same PCB... I put some details on the "beyond the Sanguino" thread. Graham Daniel.by grael - Controllers
These are my intended pin assignments for the single PCB Arm Cortex-M3 based CNC system I'm designing. (see attached gnumeric spreadsheet) Even after losing quite a few pins to parallel power duplication and higher functionality state control, a 100 pin package has plenty left to handle what the Repraps currently do, and a lot more as well. Major features: 4 symmetric dual full bridge driversby grael - Controllers
Manual entry: DIY design loosely designed on the McWire, but more heavy duty. Now designing Arm Cortex STM 100 pin controlled all in one PCB with integrated 4Ch Stepper control, with the various additional I/O to complete. 4'th axis on board to be stepper motor control of extruder. Graham Daniel.by grael - RepRap Host
The Eagle free package does have autoroute, but it has some quirks (most CAD packages have their own quirks) I'm trying to do an all in one CNC PBC design with Eagle at the moment, first time for me. Absolutely critical: Don't meddle with the grid size when laying out components... you will put the components out of the connection grid. These took me ages to find: edit/net classes: this is tby grael - RepRap Host
The low step size stepper motors are pretty high torque... not sure if the reprap control circuitry allows step control of the extruder motor though. I'm certain the larger size 1.8 deg step size motors could turn a tiny screw thread. Graham.by grael - Mechanics
They do sound too expensive. Isolate the supplies though, and you can series up the heat differentials to gain a far bigger delta.by grael - Mechanics
Has anyone tried using a peltier effect heat pump to purposefully create a fast thermal gradient along a piece of thin walled stainless steel ? I'm thinking of snug fit aluminium plates sandwiching a peltier heat pump , and with fingers drilled for tight fit over thin walled stainless steel tubing. So, the heat pump is actively enforcing the differential, and after the power is regulated sufficiby grael - Mechanics
Does anyone use 1.8 deg per step stepper motors for driving the plastic filiament ? If not, is it just a question of needing another channel of stepper motor control ? Graham.by grael - Mechanics
Annirak, No, I didn't notice that. I'm at the stage, where I've looked at what's around and well known, looked at what's in my stock (out of date Atmel of different sizes, FPGAs, CPLDs from back when I ran a design business), and my nwer stock of Atmel for a small project, and untouched STM32 Arm Cortex, and I've made the decision to go with the STM32. It will take me longer to get results than gby grael - Controllers
It's a nice luxury to think about having an FPGA/CPLD and a Micro on the same PCB to run a 3/D printer/router, but the atmel seems to be doing an "OK" performance already, esp after recent revisions on the arc plot calculations (which could be done on the PC anyway) I see the Arm cortex is available via NXP, as well as from STMicro, which is where I got mine from. The first issue of NXP LPC procby grael - Controllers
Hmmm... We're looking at two sets of tradeoffs. One, is loosing the inbuilt ADC, which typically would only be used for thermal measurements. That could be done on a dallas 1-wire bus anyway. There's a little bit of accuracy required on the timing for that, but I'm sure it's out as a soft solution to fit on a CPLD anyway. The alternate tradeoff, is having to run time intensive tasks requiring aby grael - Controllers
Andy, you have a point (I looked up spartan arm cortex and got this: ), but I would be missing out on the dual ADC and the dual banks of analogue 1-of-8 selection. Sure, I could do the analogue with a cheap microcontroller, but, that's what the Arm Cortex is anyway. These are digikey pricings for two of the FPGAs that ARM list as being compatible with a core of that size: This, for the STM3by grael - Controllers
Hi Andreas, I'm in New Zealand, evening here, and summer. After I last posted to this thread, I saw a renewed thread initiated by Chris, in which it appears he's addressed many of the issued discussed above. He's struggling with code space though. I follow your reasoning, indeed many PC operating systems have poor resolution on their available interrupts, so I understand the natural progressionby grael - RepRap Host
Thanks Annirak, I think the price is not that bad if you look at what they can do, except for the ommisions compared with other modern micros. They are a natural for a high speed printing controller if the quantities are too small for an ASIC, and if you want small foot print and code security. However, I've asked around, and it seems that Atmel are not doing much volume of the product since theby grael - Controllers
Hi Annirak, I haven't done enough FPGA work to have a feel for device size required (model,complexity), but I like their flexibility. It's quite possible to implement the quadrature encoding, position counting, terminal stop count reset, and a custom addressing system, even LCD control in an FPGA, and I'm sure complexities are up, and prices down from when I last played with one about 6 years agoby grael - Controllers
I've been giving myself a crash course on REPRAP over the last few days, and I'm surprised, I saw in one document... I think in a reprapper's blog, that the PC was sending out the step commands, and that they were buffered into a quad EEPROM eray. Now, I see this thread, where g-code is being used, and is requiring an 8 bit micro to do some fast maths on the spot... albeit a rushed implementatioby grael - RepRap Host
The FPSLIC by Atmel does much of what's been discussed on this thread. It has no ADC though. It's possible to run charge/discharge cycles through external hardware in series via a capacitor (i.e. a PTC resistor), and time the transition periods, but it's messy. I think the IDE is freeware. Price: (size with smallest FPGA, in secure mode (on chip configurator) 144 pin LQFP ! I think, that you cby grael - Controllers
I velly surplised that no one hav sugestered a WepWap RireRap mashine valiant yet. The WepWap rap the rire awound the foo hole leggies of eech componerent and groin the leggies with an elechical costechion to eech other. A spitter mechanism take a the insultation offa the copper wir to bondi to the plateleting of the leggies. Noting: no murcury or gallium are drip out of prastic when hot meltinby grael - Controllers
Possibly Wade's problems with the eepc: I believe it has flash disk instead of a standard hard drive. 1G may be enough memory for a PC file swapping to hard drive, but the issue may be file swapping to Flash disk being slower. They use large sectors, but there are still significant delays with the write times, and I suspect, no facility to overlay writes to very many pages at a time. This wouldby grael - Controllers
Thanks Wade, in the interim, I've posted my thoughts on the electronics platform here: , and I appreciate your information on file sizes I will hunt out the info on Zach's motherboard, but I'm thinking I need more power on the embedded side, for resolution, and to avoid glitches. I don't have one yet... Lots of work ahead for me I thinkby grael - Controllers