shadowfiend

I seem to remember reading that one of the recent Cura versions was supposed to look for the sharpest 'concave' corner and put the dimple there. If anyone else could confirm this, then one way would be to create a tiny corner running from top to bottom on the back face of the part. It's just an untested theory, but might work :c) Cheers.

I’m PRINTING :c))) I am really happy thanks to your help dim3nsioneer :c))) This is the code that I eventually ended up using:- M109 S200.000000 ;heat the nozzle to 200C G0 Z80.0 ;Move high enough to clear the print G28 X0 Y0 ;move X/Y to min endstops G0 X0 Y200 F9000 ;make sure this position is safe for z homing G28 Z0 ;move Z to min endstops G1 Z75.7 F?whateverstandshere? G92 E0 ;zero the extruded length G1 F200 E20 ;extrude 20mm of feed stock ;G92 E494.38289 ;adjust the extruded length ;Put printing message on LCD screen M117 Printing... I followed your instructions and tried each line of code with my finger on the power button just in case :c) After all the startup code was working I pasted it into the big gcode file and deleted the code that had already been printed. To make sure everything was lined up and there was no chance of a collision I used the print speed adjustment and took it down to 10%, I disengaged the extruder but heated the nozzle up and set it going. This was good because it helped to smooth out the plastic at and prepare it for good layer bonding . It’s done a few layers now and things are not lined up too badly. I’m amazed it worked at all to be honest because I had not saved the gcode before I started the print and had to ‘trust’ that the rotation and scale had been applied exactly as I had done the first time. I’m gradually increasing the speed and all is going well. Many thanks dim3nsioneer, I really am grateful for your skilful help. Very best regards. Ian.

Sorry ignore my last coment.

Whatever I put in the gcode file for the G28 X0 Y200 just gets ignored and the printer just goes to the front left position so I have to power it off to avoid a collision. Also I would assume that the layer view would show the change in the blue line for the toolpath, but it is not. There must be an override that is taking precedence and I've no idea where to find it :c(

Sorry, dim3nsioneer I must be having a senior moment, do you mean to enter this in the start.gcode or in the gcode file for the model? What I was saying was that I cannot seem to make the printer do anything different in the starting moves. I'm rather confused :c/

Hi dim3nsioneer, Uncomfortable yes, but with helpful folk like yourself, I think I can get it all sorted :c) I have worked out that the print stopped at 75.6mm or 378th layer. I'm printing at .2mm layers. I don't have a heated bed, but a light bulb powered heated chamber and the print is stuck down really well, so no problems there. The main issue is understanding how to set the homing position to the back left in the gcode, is there an override that is in firmware? Can't seem to figure this out. Printrun/Pronterface looks great, but I think I just need to fix the homing thing and I'll be away. Thanks bud :c)

Hi Makers, I have a customer that needs two copies of a part that is 150mm tall. I have already contacted tech support but have had no reply since Thursday. I have had three failed prints and it seems that pythonw.exe is crashing every time and the print just stops. I have been looking at this method:- 2 ways to resume print from last layer But because the print is still sitting on the bed, the only place I can home the nozzle is the back left corner, otherwise the x axis rod would hit the half printed work. I don't have much experience with Gcode and the like but I have tried changing the start.gcode settings to change the homing position, but it keeps trying to home to the front left. Also if anyone knows a workaround to prevent python crashing on a large print I would be most grateful. I have ordered the UltiController but that won't save my bacon this time. I'm running Cura 15.02.1 on Windows 7 Ultimate. Sorry if I missed anything out but I'm really stressing over this, the prints take about 38 hours each! Many thanks and kind regards.

I figured out what the problem was :c) It was caused by proximity of the wiring to the pump to the thermocouple. Being lazy just to test it, I just plugged the pump into the socket where the fan goes. I've now got the pump plugged into the UM mainbord and zero interferance!!! Result :-P Now comes the plumbing bit, which should be interesting and I can the do a test print :cool: Cheers, Ian.

That sounds like a a plan Avi, good thinking. I'll report back soon to let you know how I get on. Many thanks :c) Ian.

Thanks Avi, How does one go about changing the PWM frequency? I couldn't see that option on the robotfuzz web application. I was hoping that I could run the water pump just like UM cooling fan, start stop and speed control. I might try to dig out an old transformer to power it though. Cheers.

Hi Neotko, As my machine is the UMO I did'nt have this option, also the washer that I made has been carfully ground very flat on a dimond sharpening stone and the edges rounded off. I suspect that the UMO+ shroud would get caught on the print as you say :c) Unfortunately I'm having a problem with the water pump at the moment. Let me try to explain. I have connected the pump to the cooling fan power and it runs fine and I can control the speed from Cura, but there seems to be some interferance with the temperature sensor when the pump is running. I have tried changing the firmware via this utility:- http://marlinbuilder.robotfuzz.com/ I changed the 'Increase PWM frequency' to 'off' and 'on' and I'm still getting the problem. Does anyone know if 'Increase PWM frequency' is the same as 'fast PWM'? I'm Drawing a blank on this one. I will be able to test if the nozzle will get cooled too much after I fix this problem, but there is a small gap between the copper pipe and the nozzle. If there is a problem I'll buy some insulation :c) Many thanks. Ian.

Progress has been made :c) I Used some gardening wire to secure the 3 parts before soldering. I covered everything in flux before holding the part over the gas stove and the solder flowed quite nicely :c) Not bad for my first attempt :cp Cleaned up a bit. All assembled and just waiting for the silicone tubing a water pump. I warmed up the printer to 242C just to see how hot the parts got and it did get very hot, but I think the water cooling will bring the temperature right down to useful levels :c) I'm hoping to get some video when it's all up and running, but it's going to be difficult to get decent close up shots, we'll see :c) Cheers. Ian.

Apparently you can also use salt or fill with water and freeze it. In the end it was quite ease to bend by hand. I used an old bit of PLA that was just the right diameter for the tight bend. I also annealed it a couple of times which made it easier to bend. A printed bending rig would be brilliant :c) I changed the shape to make it easier to attach the silicone tubing. I have looked at a few plumbing videos and also tested the flux out on some scrapps and it seems to work well. I'm going to solder it today :c) Will keep you posted. Cheers.

Thanks for your reply aviphysics. I have ordered this 12V pump from ebay:- http://www.ebay.co.uk/itm/171555075839?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT Rated voltage: 12V DC Max rated current: 400mA Static flow rate: 240L/H From what I read on the forum I think it should be ok, but I will bow to any information to the contrary ;c) I did consider air cooling but I thought that there may be excessive noise and was unsure if it would be efficient enough to cool the part. It's all guesswork at the moment. I take your advice about the risks of water leaks seriously and will proceed with caution. However I have already bought most of the bits I need, so I'm going to keep going the water cooling route for now. Regarding the soldering, this will be a make or break for the project as I am trying out new things. I know that flux is the key to getting the solder to flow properly and getting the parts all lined up is going to be a challenge. I read somewhere in the forum that in order to bend the copper pipe without kinks, you can fill it with sand and this will minimise the localised stresses. I'm just waiting on the parts to arrive now so I'll let you know how I get on. Cheers. Ian.

I have ordered some bits from ebay so that I can make a start on the cooling duct, but I would like to be able to control the water pump as if it was the hot end fan. I'm not that experienced with electronics and would apperciate if anyone could offer advice on how to do this. I don't need anything fancy like temperature control, just a way to vary the speed from the cooling parameters in Cura. Hell even if it is just on or off would be ok. Many thanks.

I have been doing some tests and have come to realise that Tom was correct:- On the first few layers the washer is cool and works well to flatten any corners that dare to lift up. However as the washer heats up, it also starts heating up the plastic under it and it also becomes more sticky which is why I'm getting this dragging effect. So I have decided to to make a water cooling ring from copper tube and solder it to the washer plate. New design for copper pipe cooling ring :c) This was my first attempt at making a cooling duct, but dicided to scrap it because it would be dificult to seal it water tight. Can anyone please tell me if I can run a water pump from the hotend fan power cable? Many thanks.

Here are some pictures, please let me know your thoughts. CAD designs All attached to the hot end These are my first results Ok so print No 1 was binned because the washer was touching the nozzle and everything got too hot and ended up a right mess. I made some modifications to the metal parts and ground down the hole in the washer plate to open up the clearance and the temperature was much better. To attach the washer to the steel plate, I was going to try to solder it, but that proved a bit tricky without flux :c) so I ended up using some scraps of ColorFabb XT and heating it up on the gas stove. This worked really well and much cheaper than epoxy! I can adjust the height by turning the pairs of nuts on each hot end bolt and I found that about .2 or .3mm above the bottom of the nozzle seems best so far. I am not using a heated bed, fans or any other heating. I'm using ColorFabb XT at 242C at 50mm/s. The prints are by no means perfect, but the washer really does keep the corners from lifting up and everything stays flat. If I go less than .2mm the washer eventually starts dragging the plastic about causing dents in the side of each part and eventually a squeaking sound as the washer presses too hard against the plastic. This could be because I'm not currently using any fans though. I'll keep you posted on any developments. :c)

Update! I have drawn up the designs and have built version 1 of the Print Flattening Disk! However, there are some issues. I must have got some dimesions wrong beause when I assembled all the parts the washer plate and washer were touching the nozzle. Also the printed brackets could do with being a bit taller, but I tried a test print anyway and found that the washer was pulling too much heat from the nozzle and warming up the parts being printed, resulting in a bit of a mess. Tom, I might invest in some Kapton tape and the ceramic tape you mentioned. The crossflow fan approach is very interesting and I have looked into this before, this flattening disk is a kind of side-step idea, but my main plan is to emulate the way the commercial printers work with the chamber heated to 70 degrees C. I have been on with this for months! Picures to follow, possibly video :c) Cheers.

Thanks for your reply Tom, I was kind of hoping that some of the heat may help to flatten out the layers. From my research the ideal temperature would be just below the glass transition point for any given material. If this happens it will be by good luck than good management ;c) Also I'm experimenting with soldering the washer to some thin steel plate in order to mount it on the hot end blots. This will act as a heat sink, so it 'should' not get too hot. I'm hoping to get some pictures of the design posted soon. Oh and by the way, I will need to remove the cooling duct at the moment, but if this works, I might not need it :c) Cheers, Ian.

Hi guys, I have been getting frustrated with sharp corners curling upwards and despite having a semi-working heated build chamber the problem persists. My usual solution is to intervene with an old butter knife to flatten and cool down the plastic, trying to avoid the nozzle as it zooms about. Then I remembered reading that some of the nice wax printers for jewellery and dental applications have a flattening plate that comes over and smooth’s out the material before moving on to the next layer. This got me thinking. I could mount a steel washer centred on the nozzle and mounted on the four M3 bolts of the hot end and use fixing nuts to adjust the height away from the nozzle tip, this might do the job for me. Think of it as a kind of circular iron ;c) So I was wondering if anyone here has any experience of this and if so, what were your findings? Best regards :c)

That does indeed sound like a very powerful combination of features. I would also like to sound out another sub-feature that may well make Cura even more powerful. If you consider an animation program like Maya, almost every parameter can be changed over time using a curve. Now imagine the power of the ‘spread sheet’ table, with the additional option of adding a curve that would allow any single parameter to be accurately controlled, not over time, but instead over Z height. In addition ‘real time overrides’ to any of these parameters would be totally awesome :c) I am aware that with this feature there is the potential to make some situations during a print that could mess things up or even break the printer, but with an appropriate disclaimer, saying something like “Please note that this is an experimental feature and may be dangerous to your printer”. I would love to see where Cura will be in the coming months, I have great hopes that it will continue to improve and stay at the top of the tree :c) Many thanks. Ian.

Hi Gr5 and Daid, Any further thoughts on my suggestion? I might start a new thread as a feature request, perhaps if I explain myself better, people would be keen to have this feature. I know it is a lot of work for you Daid, but I really think that it would add a lot of value to the software. Many thanks.

Hi Gr5, Ok I may have not been very clear, I do apologise. The way the feature could work is similar to the following. So if you are using MS Windows and you open a folder there are a number of columns for name, date modified etc. If you right click on those column headings you get a dialogue where you can select more or fewer parameters, there is a huge list of parameters here but most people don’t need to go in there often. I’m not saying that you would need to check these every time you print, but only if you need to alter something specific for a particular job. Also if like you say, you want a setting to be global just remove that one column and the normal Cura parameter will take over. Daid called the feature "setting overrides", so this is my humble suggestion on how it might work. My point is that the column list could be saved in the Cura preferences and only modified if needed. I hope this makes better sense. Thanks.

LOL :-) As I said though, an 'available columns' preference would alow the user to select only the colunms that would be needed but would give very fine control over print settings. It also may be a unique feature not found in any other software ;c) Thanks.

Hi Gr5, My line of thinking for this feature was that almost any parameter could be controled on a per object basis, in the spirit of open source access to everything. In my opinion if there is a parameter that could go in this table then it should be in here. A simple 'available columns' option would keep down clutter. Do you see my point? Cheers :c)