Just to clarify emf's post. Bipolar using half the coil should be equivalent performance to unipolar.by nophead - Controllers
I wonder if this is affecting other Windows users here. Forrest didn't seem surprised by the delay.by nophead - RepRap Host
Nik, 1) Disabling OpenGl makes it start instantly! 2) The surface error value is 0.05. I haven't changed anything since I installed it. 3) Memory usage was after opening the file. The start menu shortcut just runs the .exe. No mention of java. 4) The memory usage was after the file was opened. So it looks like the problem is with OpenGl, but only at startup. Once loaded I can rotateby nophead - RepRap Host
Looks like my post crossed with emf's. A slow blow 2A fuse is not much good as fuses only blow in a reasonable speed at twice their rated current. It may protect the motor but I doubt it would protect the L298. A quick blow fuse might be more appropriate because the current should never go much above 2A with fast PWM. I agree using two coils is a good idea. Its only a one line change to the firby nophead - Controllers
I don't know where "Oh no" man came from, it was a present. When he is dropped he says "oh no". Probably a comment on my negativity! I am pretty sure magnetic flux is proportional to ampere turns, not the square. It is inductance that is a square law on turns. Yes the full coil gives 1.4 times more static torque for the same heat, assuming that the magnetics don't saturate. They may well do asby nophead - Controllers
Nik, 1) It draws the frame window and the objects window with the objects in it almost instantly but the view windows just show what was already on the desktop. I.e. they are not even blanked. After a pause there is a short flurry of disk disk activity and then another long pause before the objects are drawn. 2) I start AOI either by the start menu and then file open or double click on the fileby nophead - RepRap Host
Hi Nik, It was just the XYZ fields in the properties window that I noticed. Regards, Chrisby nophead - RepRap Host
Eric, Yes the current will build up 4 times quicker and to a higher value, 2A instead of 1.6A, but you have half as many turns so the final steady state torque is lower. However, once you get to a speed where the rise time is the limiting factor you will gain torque. If you can step slowly without skipping then you have enough torque to overcome the friction. If you can't go faster its becauseby nophead - Controllers
From the previous posts it looks like you need to import rather than open file.by nophead - RepRap Host
emf, I had a hand in calculating Eric's series resistors. I didn't realise they were six lead motors. The resistors are correct for 2A into 1.6R from 7V (the drive chip loses around 5V at 2A). If they are six lead motrs then Eric should be using one end and the centre tap. Eric, If you are using the two end connections of each coil switching to using the centre taps will reduce the inductancby nophead - Controllers
The 1N4005s obviously work as people are succesfully using them. As the only high speed switching is PWM to control the torque I expect the only effect is increased switching losses leading to slightly hotter components. These drives are certainly not optimised for speed, but with belt drive that probably isn't necessary. For high speed running needed for screw drive then you would use low voltaby nophead - Controllers
Yes I noted the diodes should really be fast recovery in my blog. I used some I recovered from a blown up PC power supply on my machine. I quickly recovered 8 fast recovery rectifiers from it but that would only do one RepRap board I think. Yes all new interesting devices are surface mount and the trend is to not even have legs, e.g BGA, QFN and DFN. If RepRap is not to be left behind on the elby nophead - Controllers
It shouldn't be too much drama for me to make some half round bearings as I do have a lathe and having spent time writing code to mill the half round indentions in the extruder it would be a shame to fill then with something square. However, my lathe skills are not the best, basically I am relying on childhood memories of watching my dad so it could all go pear shaped. I which case I may fall bby nophead - Mechanics
Forrest, I don't understand, how can you drill 1/4" hole in 1/4" bar? Typo ? I seem to remember you had a closed hole rather than a half bearing. How does the filament get past the bearing?by nophead - Mechanics
OK I will stick to human technology and make two, thanks.by nophead - Mechanics
The wiki says: "You may be tempted to make just one whole bearing and then to cut it in half. Be warned: unless you own a hacksaw with a 10 micron thick blade supplied by alien technology you will not be able to make this work..." If you can use a stack of washers cut in half with bolt cutters why does it matter if you cut a bearing in half and lose a saw cut width? It is only half a bearing witby nophead - Mechanics
Samuel, yes I got myself confused, sorry Zach. Unipolar motors do indeed have more wires because they have centre taps. You can use them on bipolar drives by ignoring the either the centre tap, or one of the end connections depending on whether you are going for torque or speed. Living up to my nom de plume there.by nophead - Reprappers
Well this stuff is all new to me but PVC definitely changes state at 85C but it doesn't become a liquid, not even a very viscous one. I read the glass transition is a brittle to flexible change. Although I would not describe my PVC sleeving as brittle it does spring back when bent. At 100C it does not hold its shape as a tube or have any spring to it. It just flops about. When I cool it down agaiby nophead - Reprappers
Well if the firmware for each head is identical it would make sense to put the id in the EEPROM, but if it is different for each type of head, as is quite likely, then it may as well be embedded in the firmware.by nophead - Reprappers
It looks like the lower temperature, 87 degrees, is actually the glass transition temperature rather than the melting point. This is what I crossed when I put it in boiling water. It loses its rigidity and becomes "rubbery" but does not turn into a liquid and flow.by nophead - Reprappers
There is no such thing as getting the indentation wrong in Python. The indentation defines the block structure. If it's wrong your block structure is wrong. It's plain to see so if it is wrong and you can't see it then it means your logic is wrong. Just like any other semantic error, it will take somebody time to fix but at least it is staring you / them in the face unlike things like :- for(i =by nophead - RepRap Host
Forrest, I don't know if this adds anything but I have a piece of electrical sleeving which is marked "PVC TUBING 105 C". It is "springy" when cold. In boiling water it becomes "floppy" but does not melt.by nophead - Reprappers
Currently it has little connection with the RepRap design because I made it from surplus parts I bought off eBay and electronics I had already. At the moment it is just a small but very accurate milling machine controller by Python script over Ethernet. I am using it to make the RepRap extruder which I hope to finish next week. If that works I will attach it the machine and use it to make the reby nophead - General
I think Ethernet cables have 4 twisted pairs and normally only two pairs are used. So you could use one of the "spare" pairs. They may get used for POE so you could get big problems if you plugged it into a network rather than a PC though. I can't say I like the idea, it seems a but over the top to use 8 way connectors for a simple two way circuit. Surely its cheaper to use two pin headers andby nophead - Controllers
If you can solder, follow instructions and do basic debugging with a voltmeter then you should have no problems with the electronics. You just buy the PCBs and parts and solder them together. As long as you stick to the recomended hardware you don't have to change any software, you can just download it. So if you can manage the mechanical aspects I think you will get along fine. The project iby nophead - General
Yes I get that from rrrf.org and a completely empty page at parts.reprap.org.by nophead - General
This has confused me as well. I think the problem is that you don't expect a heading to be a link as well. It's not normal web practice.by nophead - General
When AOI shows a negative number with more digits than will fit in the field allocated then it shifts it left so that the leading minus sign is not visible. If you watch carefully you can see it being drawn and then overwritten. Something to be aware of if you are getting coordinates out of AOI manually like I am.by nophead - RepRap Host