yellowshark

Hi, I can answer your question partially. At 3PS our core market is prototyping in the mechanical engineering area, although so far we have also done manufacturing a lot more than we originally envisaged –my early view, due to the poorer surface finish from FDM printing, was that manufacturing would not be required but clearly ultimately it depends on what the part is to be used for as we are doing a considerable amount of manufacturing. The Mojo was on our short list last year, primarily as being the cheapest “professional” printer available. We decided against pursuing it in detail for two reasons, firstly the small build plate area and secondly, at the time, I am sure the filament was only available in one colour; I think it is now available in 7 or 8 colours. It will almost certainly be far easier to use support with the Mojo as it prints support in a soluble material and optionally you can buy a self-contained washer to remove the material. You can though do the same thing with a dual extruder RepRap printer by using HIPS for support. In the end we bought a 3ntr printer as it had dual extruders and a heated bed. It is very similar to the UM in overall mechanics/architecture although clearly it has a more reliable drive system. I am inclined to think that the Mojo, especially for difficult intricate items, will produce a better job. I do note that its resolution goes “only” to .17mm layers whereas the UM will go lower than 0.05mm layers. What you are referring to as a “hollow core” on the UM is a misunderstanding. You are looking at a layer map for a piece that has been setup to print with something like 20% infill. If you setup with 100% infill you get a solid piece. The Mojo has a similar function called sparse infill. Most of our pieces are produced with 100% infill for the same reasons you need it. This is all done by the slicing software not the printer. So far we have not used ABS for prototyping, we use PLA and Nylon. I would assume the strength of ABS parts between the Mojo and the UM would be very similar. The key element will be layer adhesion and as long as the UM is setup properly I doubt it would be disadvantaged. Accuracy could be a different thing. The only way I think to really determine that is to take an appropriate part and have it printed by both printers. We tend not to print assemblies but do print parts that have to fit existing assemblies, so accuracy is often very important for us. For most geometries we will hit 100 microns accuracy and sometimes will go down to 20/30 microns – the UM ought to be similar. My personal view is that manufacturer quoted accuracies are not actually accurate as I do not believe they take into account material shrinkage. My gut tells me that the Mojo is a more plug ‘n play printer than a RepRap and if you are OK with the smaller build plate, more limited material types and colours then it could be a very good printer for you. But equally for prototyping a RepRap style printer, if it is a good one such as the UM or 3ntr, is extremely capable. I think the only real drawback is when you have to use supporting material. Unless you use a soluble material (needs dual extrusion) you can end up with the supported face being very rough unless you have time/cost to spend in smoothing it, which can be very tricky on smaller items. I must say that so far for us we have been able to work around the supporting point and have not been defeated by a design given to us. And do not forget that good product design takes into account the manufacturing environment. What is easy to produce on a CNC machine may not be easy on a 3D printer – and the reverse – we designed and prototyped a part that was to be injection moulded, only to find that the injection moulders could not produce it. HTH

Ah well that is quantum physics for you

In 2013 I had zero problems with Colorfabb filament (PLA/PHA). This year (quite early I think) they did two things – changed the pla and pha mix and relocated the factory. My experience this year is that the consistency of the filament width has dropped considerably. That is not to say it is not a good filament, it is, nor that you cannot print with it, you can. But disappointing nonetheless. I have bought some 3mm (id) bearings which I slip over the filaments so I can then easily see that they do not (or do) exceed 3.00mm

Hi my first point is that IMHO using 0.6 solid layer height when using .100 layers is probably not enough. I get the feeling, from my experience but NOT scientifically corroborated that the thinner the layer height the more solid layer depth required. I.E. if you are OK with .6mm when using .200 layers (ie 3 layers) the using 0.6 when using .100 layers (6 layers) is not enough. If I were printing with .100 layers I would use a top layer depth of at least .8mmand be prepared to go higher. My general rule also is that the higher the infill density the less solid top layers required (and of course vice versa). I also suspect print speed will impact i.e. the slower you go the better those thin solid layers will lay down over the infill.

Me too George (ie using the floor) but I always find the Colorfabb filament to be really tightly rolled at the end. For the first time I have a roll of Faberdashery filament, being a test roll of customised filament. So it will be interesting to see how I get on with that.

I am sure you are right Don, STL was created specifically for additive manufacturing way back and the idea of re-interpreting the file back to a 3D model with all its attributes and design intelligence is improbable. It worked fine for us as all we needed to do was to match another part to the contours of the imported stp file, we did not need to modify it. What I cannot remember is if we were able to pick up the dimensions from the imported file, which could be very useful depending on what is required.

Ok the free version of InStep is limited to 3000 faces. I am happy to take your much larger file and try it as I have the Basic version which does not have that limitation - although g*d knows how long a million+ faces will take to process. I will message you an email address and if you send me the file I will try converting it to stp and mail it back to you. Plases note that the quality problems can occur; they are not guaranteed to occur. EG I would not expect a Solidworks stp file going to an Autodesk user to have problems (no guarantee though

...btw I assume you realise that scanto3d is only available in the Premium version; unless that changed with the 2015 release

OK, well you can use the free version of InStep to import an stl file and export an stp file - see solveneering.com. BUT you are limited on what you can do with it in Solidworks as far as I remember. You can extrude it but I do not think you can edit features. Worth you having a look at no cost. Having said that it may well depend on the quality of the software creating the stl file and indeed the InStep software, but moving between file formats and software can loose design intelligence. Best test is probably to export an stl file from Solidworks, run it through InStep and import the stp file from InStep

Ok can you please clarify – which of these statements is/are correct. If I start a print with a temp. below 220 nothing is extruded. If I start a print below 220 I get extrusion but then it stops during the print If I start a print with 220 or greater I can complete a print If I start a print with 220 or greater after several prints I get a blockage Also after you get a blockage have you checked the surface of the filament in the Bowden tube? If so is it Pretty smooth Has some small teeth marks Is pretty rough with deep teeth marks Are there any stretches along the length that have been flattened, ie no longer round.

It may not be relevant to your printer but I have a glass tray which sits on top of the bed and self locates with 4 magnets. As the bed is lowering to the home position after the print I slide the tray off and reset the bed and extruder temperatures. Often I can then slide the model straight off the glass tray and then put the tray back on the bed. It only takes a minute or two for the bed to get back to desired temperature.

.... with PLA

Thought so George Which brings a long standing question to my consciousness, when/why would you not use 100% fan?

I have not fully read this thread but I think I had a similar issue recently. I had a slatted triangular structure that I printed on its side - so I had triangular points sitting on top of each other but with a vertical space between each one. I put supports into these areas with Meshmixer. On first print I got the curled up points. For the 2nd print I doubled the scale of the model to get more material at the pointed area and I also pushed the cooling from 50% to 100%, thinking that maybe the heat at the extruder tip was pulling the material up. The 2nd run was successful; whether it was one of the changes or both that gave success I have no idea.

Ditto; never seen it and yes a scrape rather than a hole is more logical. We probably need a materials expert to answer this one.

I cannot answer that directly but I dip my nozzle in boiling water and then scrape it off (easily) with a flat bladed screwdriver.

Neither am I

Personally I would print a test cube at 200 and then again at 195. I do not know the characteristics of this blue filament but .100 at 30mm/s with 200c is OK on most of the filaments I use. See how low you can go then give that temp. a try. It may be that 40% infill will not cause retraction, it will depend on the geometry and object size; worth a try, you can always kill the print after a few layers. Most of the stuff I print is smallish engineering items and using 100% infill neither adds significantly to the time or the material used so it is not a subject I ever really think about. I did print the base for a building which almost covered the entire bed and I used 40% for that, which probably gave similar spacing to the holes in your 20% print. I did not suffer the problem you are finding; I was using .200 layer depth

Ok need to be careful here as various (standard PLA, PLA/PHA) filaments will have different optimum print temps and I have not used the blue white. You are quoting a range of 0.1/40 to 0.2/50. For most filaments at .1/40 you should not really need to go above 205 and .2/50 above 215. Today I have been using a Faberdashery filament at .3/60 at 215 and .1/30 at 205 (99.9% certain 200 would have been fine). If you are saying that with your settings nothing will extrude if you go below 220 then I suspect you have a problem somewhere, probably filament partially blocking the path and using 220/230 is hiding a problem that you would e benefit from fixing. Of course it might just be the white blue. Do you have other filaments that you can run perfectly at other temps?

btw with Colorfab and those settings I do not think you should be hitting 220 let alone 230

... I should add that I too started to suffer from blockages which is why I carefully measured a significant length of the filament. Colourfabb kindly and very quickly sent me a replacement spool but I had the same problem. It was Dutch orange, a filament I had used a lot. Maybe I was just unlucky but life is too short....

Hi, Colorfabb used to be my filament of choice. But now I no longer buy it as I have found it to be very poor in terms of consistency of filament width. It used to be spot on 2.85 but now it seems to be all over the place. Interestingly, but maybe not surprisingly, it seemed to coincide with the relocation of their factory.

Great looking job Didier, I am just wondering how you did the world map?

Hi Bob, I am sure with experience you will get great prints from S3D, it just needs practice! I was long windedly making the simple point that changing settings midstream can create artefacts, which you seem to be suffering. You just need to manage that, maybe making the changes incrementally - he says with 0 experience! Perhaps if you used thicker perimeter walls they would absorb the change before you printed the external wall, for example.

... of course it may be that that has nothing to do with it. Take the filament out of the Bowden and run your finger along it- if you have very noticeable teeth marks then your drive wheel is set too tight and continuous retraction will almost certainly give you what you have just experienced. The filament in my Bowden tube is pretty much as smooth as the filament waiting to go into the Bowden tube