yellowshark

For cleaning up a print, then I use a modelling knife and a set of files. If you can then pay for a set of proper jeweller's files; they will do the job better and last a lot longer

Yup I think @JohnK 's figure of 0.5mm added to ID is a good starting point. We have certainly used less, but it depends and some experimentation will almost certainly be required. We have not done enough to get an exact figure for various filaments, we tend to use "inserts for plastic" these days where possible.

When the plate is sprayed with the hairspray you can smell it - the same as if you are spraying it on your hair. After that I do not notice it - i.e. the heated plate does not increase the hairspray smell. No you do not clean it for every print; it normally lasts me several weeks, sometimes longer. I have not been doing many prints recently, none over Xmas, and I last sprayed the plate about two months ago. I did a print last week and it was fine. I think it does depend on the model, but if there is a brim then normally I can remove the plate from the printer and lift the brim with a small screwdriver and the part will often release immediately. Otherwise, having removed the plate from the printer, I can remove the print after about five minutes.

If you run your printer from a usb attached laptop using Repetier Host, then when you load the gcode RH will display a print time, before starting the print, which in my experience is always pretty accurate. You will also get an exact print time on completion by looking at Job Status under the RH Printer menu.

Lol yes it does say it on the can. I use L'Oreal Elnett Satin, from Waitrose but no doubt stocked in other usual places. I do not know if brand has any implications, a conversation best had with a member of the fairer sex I suspect - I was looking for extra strength and that is what Waitrose had on the shelf. Also no idea what impact this may have but my process is - warm the glass plate to my operating temp. of 65, remove plate and apply two layers of very light spray with 20 secs between each layer, replace plate and wait for temp to get back to 65 and go. An application will last me several weeks to a month or so. To clean off the residue before reapplying, just hold the plate under a running hot water tap and wipe of with a J cloth or similar.

Nope it needs to be warmer. I cannot remember the last time I had a part lift from the bed, at least 18 month plus. My settings are... Bed with glass plate Adhesive - two coats of lightly sprayed extra strength hairspray Glass plate heated to 65c - as measured by digital thermometer over the area covered by the first layer. 1st layer resolution .3mm Printer speed 20mm/s Printer door open and roof removed Fans off Extruder temp. 210 - if I am doing a print with the extruder temp. below 195, then I might drop the 1st layer temp. down a bit from 210, it depends on the model. I nearly always use a brim these days. After 1st layer has completed I drop bed temp down to 50-55 and start adjusting the extruder temp to desired temp. I start the fans after layer two, building up to 100% by about 1mm model height. I always watch the first few layers go down; if you do not you cannot tell what, if anything, has gone wrong. If I did get a lift I would clean the glass plate and reapply the adhesive. If that did not solve it I would go through bed levelling and nozzle to bed distance processes.

Solidworks has a library of just about every thread there is but you have to pay for it; maybe if you have the top level of software it might come free? Not sure how you create yours but e.g. for a threaded bolt we create a helix of appropriate dimensions, which is a pathway and then extrude a triangle along that pathway.

For PLA I use extra strength hairspray. Everything stick, large surface area or small, and comes of the bed as it cools down; so for me it is optimal for both aspects.

I calibrate the bed levelling normally using a cold printer. I calibrate the nozzle the bed distance by printing test cubes so that is always hot.

Ah I think you misunderstood me. When I said the 2nd model was too big, I meant that it's physical dimensions were too large to fit the build plate, not that it had too many faces.

Ditto @Neotko plus get those fans pumping. I do not print that type of small model but I would suggest 100% on layer 2 or 3 and experiment from there.

Hairspray brand optional, no messing around, sticks like glue to coin a phrase, part comes off easily as bed cools

Just loaded a 200,000 faces model into Cura OK. I then loaded a 680,000 face model in but it was too big. I scaled it to 80% and it fitted and was OK. Now whether it was still 680,00 faces or 80% of that I have no idea

In a word yes that is all you do, you need to unlock the Uniform Scale. Alternatively if you know that the reduction in scale is the same across all three axes is the same then leave the Uniform Scale locked and just enter one value. As for the holes, well it probably depends on why Cura is showing the measurements incorrectly but I assume the holes in Cura are now too big and that the rescale will bring them back close to what they were and probably they will be OK.

It also depends on the quality of the final product you want; the faster you go the lower the quality. Printing more than one model on the bed concurrently can also speed up the overall time - although that does come with other considerations e.g. print too hot and you will suffer stringing. If your feed system is working 100% you will not need to go anywhere near 240 if you are using normal PLA

Every filament on YOUR printer has an optimum temp. for a given group of print settings. To get really good prints you need to test this and establish the optimum. Generally speaking cooler is better than hotter. When I test I keep reducing the temp. until I get to a point where it has degraded - normally under-extrusion. Most major filament manufacturers provide a specification and I have never seen a maximum figure above 220c and I Colorfabb was 215c - I am talking here about normal PLA not brassofill etc. These days I never go above 210 and am often under 200. I have dropped 10-15c since first joining the forum. Too many people on the forum quote too high a temperature. I suspect that probably results from the problems with the UM feed system - but pushing the temp. rather than fixing the feed system does you no favours. So concentrate on the optimum for your printer rather than worrying whether it is too low or too high, especially compared with other people's views. And do not forget that a different colour from the same manufacturer can have a different optimum temp. - the colour dyes have an impact

Last year I printed something from a scan. The raw model had 700,000+ faces and that plus down to around 400,000 faces screwed several pieces of software I sometimes use; I did not get as far as Cura and printing. I decimated down to 80,000 and that was fine but I have no idea if that is a good target to aim for or whether it is smarter to go lower or higher; my output normally comes from Solidworks and is not something I pay any attention to.

Unfortunately we will never compete with China in general or injection moulding where a piece is from a large run. I designed and made a very nice set of chess pieces for myself but if I were to print them again for sale I would charge 400-500 gbp, too much for plastic

Just in case it is not the coupler, whose filament are you using and what is the manufacturer's specification for the diameter?

OK, Using the Cura advanced tab, set initial speed to 20 mm/s. It would be useful to know what speed you have been printing the 1st layer with? Not sure what the 0.6mm nozzle impact is, if any, but most people use 0.3mm for the 1st layer, so it would be worth swapping to 0.3mm to see. You say 60degrees, it would worth trying it a bit warmer, say 65, this does vary with printer/filament. Are you using any adhesive? If not that will help - most use adhesive, not all. I use extra strength hair spray, many others use special glue stick or a sludge made from it. Make sure you filament is flowing properly before starting your print. If you cannot manually feed it before starting (say 30mm) then if you are not using a brim then use a skirt, say minimum distance 30mm - the expert setting menu displays the settings for the skirt. I assume you are saying the front door is closed. I do not think this will really have an impact, either way but I print PLA, including 1st layer with door open and the roof off. Your elephant's feet - this will normally be caused by your nozzle being too close to the bed, i.e. not calibrated correctly. Lower the bed just slightly, say 0.05mm, and again if no effect. I use a more accurate process... For the nozzle to bed distance I have a calibration test routine, using a standard cube. I have a z-offset in the start gcode routine which makes it easy to adjust the nozzle to bed distance automatically and accurately. I use a binary chop style process to adjust the distance. On my printer I need a z-offset to allow for the glass plate; I do not know how it works on the UM2 with a glass plate. If you do not need a z-offset then just set it to 0.0. So… Having set the distance during levelling using the standard sheet of paper, and assuming my z-offset is 7.1mm I will print the test cube (1st layer or 2 only). Then I add 0.04 to the offset and print again If 7.14 gives a better result then I add another 0.04 If 7.18 gives a better result then I add another 0.04 etc etc If 7.22 gives a worse result then I subtract 0.02. If 7.20 gives a better result than7.18 I will try 7.21, meaning either 7.20 or 7.21 is the correct offset Referring to the above, if I find that 7.15 is worse then I go the other way, setting the offset to 7.10 etc etc

It could be your filament, cheaper filament is made by cheaper equipment and cheaper processes and of course in China by cheaper people. Cheap means poorer performance and irregular diameters which will clog your feed system and reduce flow. Take your digital micrometer and measure along the filament for the length you need for the print and ensure as a maximum it is not exceeding 3.0mm. If it hits 3.0mm then it is not good filament by the way if it is meant to be 2.90. Two of the biggest suppliers ColorFabb and Faberdashery manufacture at 2.85 and every time I have measured it it has been within a tolerance of +/- 0.05mm. If you do not have a micrometer then you ought to get one.

Ok, well your point about a variation on the z axis homing could be a point although I do not think I have heard of that one. I will put that to one side for you to investigate. If your other layers are OK, you say the top layer is fine, then to my mind that points to the bed to nozzle distance - if you do not adjust it accurately you pic shows what you will get.

None with PLA which is the vast majority for time. If it is a 4 hour print job I will normally sit there listening to my hi-fi and absorbing all those nasty fumes, particles etc. I might open the window in summer if it is hot.

Yup my page says there are 7 unread replies but there was only Titus's response and I get notifications of posts made an hour ago only to find I have read them a few hours ago.

It is also worth noting that at 3 times the price it is unsurprising that the Mojo beats Reprap style printers. It beats mine, which I consider just about the best of the bunch. As I noted mine cost a lot more than the UM but for that I got dual extrusion, apart from the obvious plastic parts like wiring and windows it is made 100% from CNC machined steel and alloys, came with a heated bed which UM did not but may do now and has a vastly superior feed system. The upgraded model has three extruders, water cooled extruders and automatic levelling using an infrared or something sensor. I am not trying to knock UM, as I already said it is great value for money but in the end you get what you pay for. which is why the Mojo beats Reprap on print quality