The thing I am printing is round, I found something you wrote about arc compensation nophead, could this be responsible? Georgeby gsport - General
So on futher investigation it seems like the printer is just laying down too much material. I dont understand why this should be. I have double checked the calibration of the feed and Z axis (and X and Y while I was at it) and they are fine. I have now told it that the material is 3mm (rather than the 2.85 it really is) in the hope that that would trick it into putting less down, but it just seby gsport - General
It doesn't seem a problem until quite a few layers are down. By layer 16 (4mm of height) one side had curled up nearly a mm but the other side was OK. The base is nice and flat. Bed temp is 65ish. I haven't cleaned the glass with anything yet, I haven't felt the need. Georgeby gsport - General
You just have to dive in. I took the plunge just over a month ago and it has been a fairly steep learning curve but the help I have had on here has been fantastic and has got me past the poorly documented parts (or perhaps the parts that I couldn't find documentation for). My kit was a relatively new one (Longboat Prusa) and turned out to have a few errors in the design of the hot end that set mby gsport - General
So I fixed up my hot end which seems to work well now and re-calibrated the feed rate. I realised that my Kapton tape ripped the first time because of course as the PTFE 8mm thread broke it let the tip move down to hit, but I am printing on glass now which does seem really good. The problem I have now is that the outside perimeter of whatever I am printing "curls up", so as the layers lay downby gsport - General
Thanks nophead. I have made the new parts now and went with aluminium for the top section in the end to act as a slight heatsink. I also moved the heater block down to the very tip to try to help create the optimum temp gradient. Need to silicone the heater resistor and thermistor back into the block and wait for it to set then will give it a go... If it doesn't work well then I have plenty oby gsport - General
Thanks for the detailed reply nophead there is a lot there for me to think about. I had been under the impression that PTFE was fairly vital in getting the smoothness of movement and low friction we need, but if not then it opens up the possibilities. It also seems desirable to have as few junctions as possible as these are a point of potential weakness and leakage. I think I am perhaps overby gsport - General
Thanks nophead, not wishing to be rude, but how do you know where the glass transition zone falls? It would obviously be very useful to be able to see inside or have some other way of measuring it. If I can take this as a solid number then I will probably use it when deciding the position of ventilation holes to the ID. It seems to me that the PTFE has a thermal conductivity so low that you canby gsport - General
Thanks aplavins, that seems logical. So maybe what we need is a short connecting section between the high conductivity melting section and the low conductivity PTFE section which has a moderate level of conductivity (maybe 20-50 W/m.K) where we can be fairly sure the glass transition is occurring? In which case steel or stainless looks pretty good... And this section obviously needs to be a verby gsport - General
Destroyed my hot end due to a design flaw. It was the one supplied with the longboat prusa from the reprapkitstore and unfortunately the parts have been re-jigged and the order changed slightly which puts a huge stress on the M8 thread on the end of the PTFE barrel (see here:- last few posts cover it). I can bodge it back together close to how it should be but want to make it better too. I havby gsport - General
That is interesting. So the reprapkitstore obviously misunderstood this and changed a few dimensions. In the instructions/wiki it is clearly shown the way I have it above Also my image above is absolutely to scale and you can see that there is a big gap between the 9mm shaft of the nozzle below the lip and the 10mm clearance hole in the PEEK so assembling it the correct way round would leadby gsport - General
For anyone else who has (or is planning to buy this printer). I now realise that my hot end failed (at least in part) because of a design flaw. The counterbored part of the hole in the PEEK for the brass nozzle was much deeper than the lip on the nozzle itself and also a very tight fit. While the PTFE part was too large a diameter to fit inside the PEEK counterbore. The result of this was thatby gsport - General
So having just started reprapping I have already destroyed my first hot end and need to fix it or make a new one or some combination of the two and I would like to talk about the theory some more. Having had a good long think, my take is possibly slightly controversial (or just wrong) but goes like this. 1. The feedstock HAS to mushroom at some point. I am assuming that it takes quite a highby gsport - General
Thanks Glyn. So did you loose nearly 11mm of PTFE length? Presumably you had to trim the bolts? I took everything apart and made my best attempts to measure it all. If anyone else is looking for this information:- The hole in the tip appears to be nominally 0.5 though at heat I found it to be nearer 0.55 (hard to measure this accurately though). Hole through PTFE section seems to be 3.4-3.5by gsport - General
Thanks for all the help. I wish I had known about the temperatures. I assumed that as it seemed to extrude well enough the default was working fine, when I did finally put it up to 190 I wasn't confident it wasn't too hot and it seemed "runnier" already. I am used to trying to keep the temps as low as possible and using more pressure to get better material properties.... I really dont understaby gsport - General
So I started taking my hot end apart to put thermal grease on the threads for the heater block and everything is in a very bad state:- 1. The thermistor has come free of the block (no biggie) 2. The heater resistor seems to be loose in the heater block, I think that there may not be much silicone holding it in but wont know for sure till it cools and I get it all apart, hopefully not a big dealby gsport - General
Thanks Glyn and another reprapper. Done the calibration and luckily for me it didnt need any adjustment from the stock value. Extruded 29.8mm with 30mm of feed which is within about the margin I can measure accurately so I left it. It is also notable that everything works fine at first, what looks like the correct amount of material comes out and it feeds fine. It is only when the machine starby gsport - General
Well I switched to a glass bed after ripping two more layers of Kapton tape (for reasons that just dont make any sense; the tip was on it's second layer and was well clear yet still somehow managed to tear the tape in the shape of the perimeter of the part). So far (three attempts at one layer each) the glass seems great, so thanks for the tip (the only glass I had was a piece of 1.7mm picture fby gsport - General
Made a crucial discovery. Turned out that my electronics were getting too hot. They really didnt seem that hot to the touch but I started getting weird shapes (rather than the circle I was printing) and on further investigation I found that the calibration seemed to have totally gone off (100mm of X feed was giving 70mm of movement and when set to home the carriage kept stopping as it obviously tby gsport - General
Thanks for the replies. Might try the glass sometime, seems like I could leave the tape underneath so would be very quick and easy to try. I was impatient last night and just turned it on and it seemed to dry out fine. Once the Kapton tape was on the bed the IR temp readings seemed good, seemed to match the readings pronterface was giving me within 2 or 3 degrees. Unfortunately my prints totalby gsport - General
Ahhhh... good point... I guess one of my first test prints will need to be something handed to check it... Wondering how long I need to give the kapton tape for the soapy water to dry off... keen to try a print but dont know if using the heat of the bed to dry it off quicker is a good idea.... Also... should I have used high temperature solder to connect my main hot end resistor? It seems toby gsport - General
My Y axis was playing up like this but I just moved the micro switch to the other side... not very elegant but very quick. Got everything working (I think) and about ready to try my first test print?!?!? Do I just whack strips of the Kapton tape across the bed or is there a system to it?... Ahhh found the tips about soapy water.... Sorted. Can anyone remind me what size the nozzle is on theby gsport - General
Thanks Another Reprapper that was absolutely what I needed thanks for taking the time to type all that out. Got sprinter across to the board with configuration.h edited to the correct board only for now, did a quick movement test and the calibration seems great with the standard values (previously it was out by about 5%) Georgeby gsport - General
Thanks for that. Slic3r seems to work now. Got Arduino modified with the sanguino file (just the top one off that list 0023r3) and the board identified and I think that Arduino is happy now... Are you saying that with the pre-installed version of sprinter I cant edit configuration.h etc? so I absolutely have to reinstall a new version? Or do I just modify the configuration.h file from the spriby gsport - General
Thanks Mark, I got pronterface installed and I can move my axes and extruder motor WOOHOO!!! However I am struggling with Arduino 0023 (which I assume I need to access the calibration files in Sprinter which came pre-installed on the board) Windows found drivers for it and installed them and looking on the device manager I dont have anything that looks like the board apart from a USB serial poby gsport - General
Thanks Another Reprapper, Thermistors switched over and waiting for my silicone to dry (really glad I put junction box on the edge of the heated bed and under the extruder plate for these connections). Busy looking at software and firmware now... Georgeby gsport - General
ARRRRGGGGGHHHHHH Having thought that I was just about ready to start connecting the printer to the computer I just had a small package from thereprapkitstore containing two new thermistors "as replacements for the incorrect 2k ones sent out earlier." Thanks a bundle, presumably this error was spotted a while ago, but rather than email customers to warn them he just waited to inform us with theby gsport - General
Thanks Bloomoo, that seems like a good idea, I am a bit worried that my choice of wire for the heated bed is a bit thin so if I have to re-wire I will try this. I got some good thick stuff for the extruder tip but ran out for the bed and used some off an old power supply. Georgeby gsport - General
Thanks Glyn that is very helpful.by gsport - General