yellowshark

+1

George, a great post, thanks for that. Sorry for delay in responding but I was away for 3 days at the weekend and following your post I wanted to do some testing. To comment on your post. My issue is solely no. 1 dimensional accuracy. I have the other issues you mentioned pretty well dialled. Of course dimensional accuracy is more complicated that it sounds. Is the Vernier gauge accurate? - mine has never been calibrated. Also physically taking the measurements requires some expertise. Then of course if you are creating a part to fit within a 3rd party assembly, just how accurate DOES it need to be? Anyway your comments on temps. got me thinking, as did Kris’s comment on the consistent nature of the environment. Two of my core settings are non-changeable; a print speed of 60 mm/s and a layer thickness of .200. Print bed temp. I used my normal 60 degrees. For the other, extruder temp., I chose 225 for my first test (before starting this thread)- unusual for me because I never go over 220 and normally use 205-210. But, probably for the 1st time, I was using Colorfabb black filament. I found a test block I had done for this some months ago and it actually was done at 60 and .200 and the temp was 225 (i.e. the temp that gave me the best surface finish). So for my 2nd test I reduced the extruder temp to 210 and I changed my post print cooling process. Normally , once finished, I immediately remove the glass bed and leave on a glass table to cool. For my new process I left the print bed alone until the part temp. was reading 40 degrees; no scientific reason for 40, I probably just got bored at that time. During the cooling I had also removed the top from the printer. Ambient temp. was about 23 degrees. The result was a noticeable improvement in accuracy. I had made two changes so I redid the test but this time using my original cooling process, whip the print bed straight out. The accuracy fell. So I deduce that lowering the extruder temp. and leaving the part in the printer environment for a period of time are both beneficial to dimensional accuracy. Maybe I should do another test waiting for the part to get to ambient temp. before removal. I did 11 tests in all. From these I found that I could not determine any difference in accuracy between 50% fan and 100% fan. 0% fan seemed to give me worse results although bizarrely gave me the most accurate Z axis measurement of the day. I also ran some tests at 205 degrees. There was little difference in the results between 205 and 210. At no time did either temp. deliver best readings for the three axes, but 210 delivered more best times for two of the three axes. For the first half or so of the tests I had walls set to 3.6 (all tests had 100% infill). I then started to play with reducing the walls. I am inclined to say that using 1 wall gave the most accuracy – not enough tests really to be sure For the last few tests I swapped to Colorfabb Dutch Orange filament and I am inclined to say that was marginally more accurate than the Black – again not enough tests really to be sure. All of the Z axis measurements were oversized; target was 3.3mm. All of the X and Y measurements were undersized. Maybe I have a problem with my Z stage? My most accurate readings were received with Fan 50% Extruder temp. 210 No. of walls 1 Filament Dutch orange (shame as really I need to use Black) Cooling process New Measurement errors were X 80 microns Y 100 microns Z 120 microns Assuming 100% accuracy in the Vernier gauge.

Ditto George's 2nd comment. I just wipe any filament off with a rag when the extruder is heated. I do mean one day to take my nozzles off and give them to my wife, who is a horologist, to give them a nice polish with her myriad of chemicals.

Does anyone know what actions one can take to reduce shrinkage? PLA vs ABS vs Nylons – any significant differences Bed temp. higher or lower? Extruder temp. higher or lower? Fans higher or lower? Layer depth higher or lower? Print speed higher or lower? Infill % higher or lower? I am guessing that keeping the chamber temp. as close to ambient temp. as possible will help?

Makes me wonder if you get Candy Floss filament? Sure would be fun! That is a hell of a nozzle, never seen that before. If it is not that then I bet you do not have retraction set properly.

Many thanks for that George; I knew you would respond but take your point

Nice job Cleven. I am thinking that if you could relate the flow to extruder temp. required you could display the proposed extruder temp. for the job

This may be a printer thing but I cannot say I agree on the extruder temp being high. These days I run the 1st and subsequent layers at the same temp. I found that dropping the temp from, say, 220 to 210 would take some time to stabilise and would see the temp dropping below 210 during the process and I always wondered what that was doing to the pressure during the process, apart from the possibility of under extrusion whilst it was below my target temp. It has never caused me a problem although reading this thread might just tempt me to try it again as a verification.

Well I am guessing here but probably onto the chair, onto the wooden floor or into my lungs. One thing is for sure the overspray is far less than when used in the bathrooms so the subject has never worried me - certainly never seen any on the surfaces in the room.

Hi Mariem, could you answer a couple of questions please. 1. Extruder temp., print speed, layer depth, fan setting. 2. The 2nd picture suggests you are printing 3 copies simultaneously, were the previous attempts printed with 3 copies also? 3. Being curious, do you print the key element separately and then stick it to the shaft?

Lol Eldrick, you are meant to spray the hairspray on the glass not on your hair Each to their own but I cannot say I have ever found it messy, quite the opposite in fact. Brand possibly? I use L'Oreal Elnett extra strength; 2 light coats with 20 seconds+ gap

Thanks guys, I tried both Meshlab and Meshmixer with your instructions and they worked fine. LOL how on earth did I miss Quadric edge collapse decimation, so self-explanatory. As for Meshmixer, “blah blah brush reduce” does not appear in their “user manual”. Both these packages are I think very powerful/useful but for someone like me, with no background/training in meshes, they just seem to be totally non-accessible without any decent documentation. No idea how you guys have become so knowledgeable! Still now I know how to use one function J Hi 3Dcase yes I think you probably misunderstood my question. I am not trying to create an stl; I have a step file imported into Solidworks which has too many faces (88,000+) and I wanted to reduce the number, say to 5000 or below. For the testing I wanted to do, my Solidworks environment is too slow with any object with so many faces.

Hi I want to reduce the resolution of an object but having looked at various software ,including Meshmixer and Meshlab, I cannot find away to do this. Maybe the software packages have a particular command/function that I am not recognising. What am I trying to achieve? In Solidworks I want to extrude a flat plane to an organic surface and then remove it so that the flat plane now has the inverted organic surface. The organic object I am using has about 90,000 faces and the process is taking too long for testing. So I want to reduce the number of surfaces, significantly, on the organic object. The resultant quality of the organic object is not really of any concern for the testing. What I want to see is that the process I am using will "mould" a plane to an organic surface well enough for my purposes.

Yup I had the same problem and my UK supplier changed the reel for new stock they received a few weeks later.

Hi George, I am about to try PA6 for the first time - what settings do you use; I am thinking of temps and also speed as the Taulmans have a pretty slow print speed (could be just the t-glasse,memory failing at the moment)

A couple of points on the Taulman nylons. Peggy if you are from Taulman - you use "we" - it would be so nice if your tech stuff on the materials on your website could recommend a bed temp. And people be careful when using the oven. I stupidly put 845 and t-glase in the oven together, forgetting that the t-glase has a much lower transition point(cannot remember the proper phrase). The 645 came out great and the t-glase was ruined. My own fault but not a difficult mistake to make if one's brain is not engaged!

What is you 1st layer depth and 1st layer print speed? Bed temp.? Can you post a pic or two of the models so we can see the bottom surface area - a screen clip of the model in Cura would do. Have you checked and set your bed levelling? A pic of a model immediately it has completed print of layer 1 may help too.

Hi Bob, I think the pic in your post of 5th August at 11:53am is probably the way to go. Is it possible for you to post on the forum or email the model file, as an assembly? STL probably OK although a STEP file would be better. When George was talking about internal quality I suspect he was referring to surface finish rather than accuracy. Using PLA those supports a will roughen up the surface finish, unless you spend hours on post print finishing. I am not sure what those internal circular cylinders are – guides for two screws? One thing that struck me was that I might design them so they are attached to the main housing which I suspect will likely provide a better finish and increase their strength. If I can get at the assembly in Solidworks I will have a better idea.

....I am still on 14.01 too

Hi Dim3nsioneer, when you say slicing resolution, do you mean the thinnest layer height possible or the accuracy of the layer height?

It is reporting 1400+ pierced facets. I loaded it into Meshmixer and with Inspect that displayed a whole host of issues too (I am guessing the same thing). Sorry but I am a beginner when it comes to analysing and fixing meshes (never needed to) so I cannot really comment beyond that.

Looking at the pistol grip pic with two areas of under extrusion followed by normal extrusion, I did wonder if the filament is sticking in the Bowden tube. It might be worth watching the print and when the under extrusion starts then stop the print and measure the width of the filament from just before the start of the drive mechanism all the way through to the extruder.

FWIW I loaded the file into InStep which reported 1514 errors. I then exported it to a step file and Instep said it output 9 of the 10 bodies in the model due to errors. I then imported to Solidworks. This imported the 9 bodies, with errors. The 10th body that was not exported by InStep is all the walls. So a duff file it seems.

Thanks guys. I must admit that my thoughts had overlooked the chemicals present. The thought of sitting in a pool for 24 hours does not appeal! I have dropped a line to Andrew Dent, director of Faberdashery, who I know is a materials expert and I will post an update with any additional information I obtain.

You will improve the overhangs by printing real slow, 20mm/s with fans on at 100%. Strange model though. Your good side, close up actually looks pretty bad, i.e. the deck and the hull look separated - does the model have a gap between the two?. How was the model oriented on the print bed?