As I mentioned before: greater is misleading, as I don´t think the dimension is meant, but the accuracy.
Robin must reformulate the sentence, as it leaves room for interpretation.
bye, Tibor
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The greater refers to the dimension (i.e. +/- 1mm or 1%) and not the accuracy. It is common statement in engineering at least.
The below text is from the original quidelines draft text from 3DHUBS
FDM parts need to be produced within an accuracy of +/- 1mm or 1% depending on which is greater.
For example, in the case of a 40mm cube, a 1% accuracy requirement would result in a max of 0.4mm deviation. As this is below 1mm, the 1mm is leading and determines the maximum. A printed part of 40.6 x 39.4 x 39.3mm would be acceptable as the deviations are within this 1mm. Printing a cube that is 38.8 x 39.4 x 39.4mm would not pass the dimensional accuracy requirements as the width deviates more than 1 mm.
Ok, got it @Enza3D @PepCo_Parker.
The guidelines only serve as reference for when there’s a dispute. Platform wide this is a very low number. The situation in which the Hub claims to deliver according to specs but the customer claims the part was not is expected to be even lower.
Having said that, if this does happen we’ll take a case by case approach. If your Hub has a good reputation you’ll obviously get the benefit of the doubt and in some cases the refund to customer will be on us. I’m curious to hear if you guys have any other suggestions on how you feel guidelines should be applied in situations?
Hi all & @Filemon
I don’t see a big issue with the guidelines as it helps both sides to adjust expectations vs. possibilities.
But may be some fine tuning is inevitable:
1. Dimensional accuracy: May be it makes sense to add specific tolerances for specific materials, like:
PLA: +/- 1mm or 1%
Nylon: +/- 1.5mm or 1.5% (or whatever makes sense)
ABS: +/- 2mm or 2% (or whatever makes sense)
2. Dimensional accuracy: Contrary to popular belief it is still my opinion that it would make sense if 3D Hubs would provide a file to approve the dimensional accuracy (and may be other parameters).
All existing Hubs shall print this file to approve their print settings.
Instead of printing Marvin new Hubs will have to approve that they are able to print according to the guidelines.
Sure, there are plenty of models on Thingiverse, etc. for testing the printers accuracy, but if there were an official file all hubs will do the same test.
What do you think?
Cheers,
Joerg
“All existing Hubs shall print this file to approve their print settings.
Instead of printing Marvin new Hubs will have to approve that they are able to print according to the guidelines.
Sure, there are plenty of models on Thingiverse, etc. for testing the printers accuracy, but if there were an official file all hubs will do the same test.
What do you think?”
And the question still remain: How do you check if it was printed accurate? I can say that it has been printed OK. How 3DHUBS check that it has? From the photos? I do not think so. Only if you physically you sent the part there and they measure it. I do not think they want their office filled with test prints. Lets be pragmatic and realistic.
Sorry @Georgei but your comment has made me think of this episode of Doctor Who: I can just see all the staff at 3DHubs fighting their way past mounds of 30mm cubes (to within 1% accuracy, of course).
Exactly…We try to solve a problem. Not create more.
Maybe to help quell the “uprising” support can pick top performing hubs, have them try the new rules out on a few orders and see how it goes… I feel like hub reputation is something people are forgetting plays a role here! If you consistently do garbage prints then that weighs different than if you do good work consistently. In the end I feel like we can sit and bicker but till we TRY the new rules we can worry ourselves bald over them… but till we begin to use them we can’t really say much.
@Joerg_4 on a serious note, the problem with approval by file (apart from the one given by @Georgei ) is that it’s a single instance of proof. Marvin suffers from the same problem; I can take a photo of a lovely Marvin and upload it, but there’s no actual proof it was printed by me, not a friend with a lot more experience and/or a better printer. If we were to use a test print for dimensional accuracy, ignoring the problem of the 3DHubs offices being overrun with thousands of prints, there would still be no proof that you were responsible for that accuracy or if it was your print, that you would continue to deliver such accuracy for all your clients.
Quality standards need to be something that can be checked by the Hub, the customer and, if necessary, 3DHubs for any print carried out, not something that’s done once (without any real proof) and then never assessed again.
From my own experience, you guys always side with the customer for obvious reasons, and as a hub you can’t do much to argue. Complain or call out the customer, and you’ve got a rubbish review that could ruin your hub, let it slide and people are quickly taking advantage of you. Honestly as I’ve said in the past, these new guidelines seem to be adding needless power to our customers over us and for what reason?
I strongly agree with this view. Obviously, if the guidelines don’t work we will not pursue
For 2. I fear the comments below touch on some good points.
I like the idea in 1. If the guidelines work (test) we can expand with this kind of finetuning (or if necessary to work). Will put the on the list with the experts (@Robin3D)