I was also concerned about this but in practice it's not been a problem at all. For the X axis, the small adjusters that bear against the end of the smooth rods can be used to adjust the bracket so the bearing is at the correct angle. For the Y axis you must first accurately line the bearings up with the clamp (which should sort the front bearing) and then the motor bracket can be adjusted by mby MarkMarsh - Reprappers
Hi Pedro, I would try and get everything as square as possible. It may be possible to correct when installing the smooth rods but it will make it more difficult. Are the two triangles exactly the same size? If they are, you should be able to adjust the diagonal rod to square the base up. I also found that small changes to the length of the top two threaded rods made a difference to how flat thby MarkMarsh - Reprappers
Stick with Solidworks - I use Alibre because I can't afford Solidworks. Do the tutorials - after a while you should get a eureka moment and it will start to make sense - it's just 2D CAD that's either extruded or swept to create the 3D shape. You will be surprised how quickly you can draw stuff once you've got used to it and Solidworks will look better on the CV as well :-)by MarkMarsh - General
Poor connection on the direction pin for the Z axis pololu? Can you swap the drivers over or are they soldered in?by MarkMarsh - Mechanics
Check that the motor current settings are correct and that there's no binding on any of the axes - as mentioned, a picture would help I'm not sure you'll find anything more customisable than skeinforge!by MarkMarsh - General
Yes - the bed is heated to 50C - I haven't tried without heating. Parts come off more easily if you have the patience to wait until the bed has cooled :-) You only need a small amount and many glues are PVA based (I'm using Araldite waterproof wood glue as I had it lying around) so it should be an easy one to try.by MarkMarsh - Printing
I had similar problems with the RRP Mendel (though I'm sure it applies equally to any heated glass bed) Acetone is not enough - I occasionally had to take the glass off and wash it using bathroom cleaner. I suspect that some contaminants are just spread around by the acetone. I now use a thin layer of PVA glue (mixed with water - probably 2 parts water to 1 glue) - wipe it on the glass and it wby MarkMarsh - Printing
I have a reprappro Mendel and it was reasonably straightforward to build (I have an engineering and electronics background), it's producing good prints and I'm quite happy with it. The Mendel90 does look very good though. The electronics are very similar but the mechanical design looks easier to line up and is very nicely thought out. Good build log for the Mendel90 -by MarkMarsh - General
The reprappro one is B57540G0103F00by MarkMarsh - Reprappers
Can't get to my PC to check at the moment but you might be able to find it on hereby MarkMarsh - Reprappers
After much experimentation, this is what works for me. Melting / warping / bridging - you need a small fan with the air directed to the area around the nozzle (see nophead's latest blog on the mendel 90) start it running after the first layer or just where you have bridges or the layer time is too short for the previous layer to cool adequately. Adhesion to bed - either get it very clean (bathrby MarkMarsh - Reprappers
I've found the pronterface motor move buttons to be unreliable - try using G Code instructions or repetier hostby MarkMarsh - Stepper Motors, Servo Motors, DC Motors
The reprappro Mendel one is a B57540G0103F00by MarkMarsh - Reprappers
I've been having a bit of a think about this - please just ignore me if I'm stating the obvious Basically what we need to do is to cool the extruded filament, if we don't, there will be heat build up and the part will melt causing all sorts of problems. On the other hand if we cool the part too much, it will quickly go to a solid state and shrinkage will cause the part to deform or at least setby MarkMarsh - General
You can adjust the squareness of the X axis by adjusting the screws that bear on the end of the X axis smooth rods which should sort out the x axis. The Y axis can be adjusted by moving the bearing and the motor from side to side and also by angling the motor slightly. I was sceptical whilst building but I have had no problems in use.by MarkMarsh - General
My reprappro Mendel is as you describe - it works fine :-)by MarkMarsh - General
I suspect it's a cooling problem. Try the small one again with a fan blowing on it after the first layer has printed. Using a fan has made a massive difference to my prints and I can't understand why they're not standard.by MarkMarsh - General
Have you got the bracket that the idler is mounted on square to the X axis? You can alter it using the screws that bear on the ends of the x axis smooth rods. When I was putting mine together I thought that keeping the belts on the idlers would be a problem but once it was lined up properly it's been fine.by MarkMarsh - General Mendel Topics
I haven't had that but I do get random disconnects - it seems that the comms is somewhat flaky which is rather poor in this day and age. Printing from SD should show whether it's a comms problem or not and it's easy enough to try so that'd be my first step.by MarkMarsh - General
It might be worth asking again with a different subject - this isn't pronterface's problemby MarkMarsh - Developers
I get that as well - it seems that the USB connection is sensitive to electrical noise. Can you download onto an SD card and print from that? Anyone know of a proper fix?by MarkMarsh - Developers
I'm no hot end expert but 2 sounds dodgy. The diameter should stay the same until the molten zone.by MarkMarsh - Mechanics
The other reason for separating the movement of the axes is to reduce inertia. Acceleration and speed are more important with FDM than with conventional machining. I have been pleasantly surprised at the accuracy of the belt approach (I also have a background in CNC and precision machining). It is important to remember that there is virtually no force generated on the part during the build soby MarkMarsh - General
1.75mm, only PLA so far but may try ABSby MarkMarsh - General
rrr7 Wrote: ------------------------------------------------------- > i have read many comments about rail binding. i > am about to mount my axes on my first machine and > am concerned that if my rails arent exactly > straight, they may bind. i am using brass > bushings in printed holders. As other people have said, the more rigid the better - on the other hand, you need good acby MarkMarsh - General Mendel Topics
I suspect your heater resistor has shorted out - can you measure it's resistance?by MarkMarsh - Sanguino(lolu)
I'm sure this has been thought of before but I haven't seen it anywhere - how about using the same material as the print for the support material but adding a thin layer of something between the support and the printed object to make it easy to separate. This would have the advantage that the support material would behave the same as the material in the object (expansion etc) and since a lot of tby MarkMarsh - Plastic Extruder Working Group
Hi Phil, No, I'm afraid I didn't - RepRapPro replaced mine and the new one has different trimpots. Looking at the schematic (http://www.reprap.org/mediawiki/images/f/f1/Melzi-schematic.png) it's taken positive (which I think is 5v) by a 20k resistor and the RepRapPro instructions are to trim it for 0.4 volts which happened at a little less than half rotation so I'd guess it's 5k (assuming a reaby MarkMarsh - Controllers
Well, I've managed to twist the top off one of the trimpots on my Melzi board. Does anybody know what value they are? I suspect I need to change all four as they are all very stiff - is this normal. Thanks, Markby MarkMarsh - Controllers
About 20.2 (20.09 - 20.35) a bit tricky to measure as it's it's not exactly a precision component. I seem to remember from my time as an amateur plumber that different qualities are available and I don't think the stuff I've got is particularly high quality so better quality stuff might be about right. Blooming eck it's cold in 't garage :-)by MarkMarsh - General