Printing files containing multiple instances of Models

If I submit a large file( to get volume discounts) containing multiple instances of Models do Shapeways spit it up when they print it?

I ask as I just ordered a file containing 10 each of 3 different models. What I got back was 10 of one, 6 of another and 16 of the last !

Only other reason I can think of for this is that it misprinted in part and they had to re-do it and they then sent me a selection from each of the two tries.


Tom

Splitting of user files in itself would not explain duplicates (and probably would not serve any purpose for shapeways unless they were
really really desperate to fill small holes in a tray), so my bet is on reprint followed by shapies failing at "Find the Differences". Spruing might help prevent such confusions, but of course it would add cost.

When I mix different parts in one file for similar "discount" on the handling, I sprue everything together so it can be handled as a single item. That way it not only pleases the tech, it also ensures that I can identify the parts by their location on the sprue! (Some of them are almost - but not quite - identical...) I only put multiple separate items in a file if they are identical.

But I have to admit, getting 32 parts shipped from a 30-part order is a new one! Clearly they lost the will to count...

I suspect they threw in a few extra in case they misidentified some. For all we know, it might have been ten each of the Toad's Hole Railways brake hose couplings period A B and C... (of course I could be mistaken and they need to be taught wheel arrangement notation)

They are fairly big and distinct - I didn't sprue them because of their size around 25x55x36 mm - would have needed substantial sprues to support any number of them - I was going for the 50% discount

This is what the look like - to me they are distinct, but then maybe not to a person who does not know trains

To my understanding, the only modification to your file(s) is during the initial upload process where all overlapping shells are merged into single objects. From there, the file is not modified in any way. It's highly likely that something broke after printing, and they were trying to make it good.

From the day that the handling fees were implemented, I've been worried that someday we'd be told that you can have only only on shell per file. Fortunately, they have yet to impose such a rule.

In case you weren't aware.. there was a item added a few months ago to the Edit Model/Details page that counts the number of PARTS in your file. A PART is defined as a shell that can not separated from other shells.. either the shells in your file overlap such that they became a single shell, or they interlock such that they won't fall apart by themselves.

It sounds like your file would contain 30 PARTS. Even though Shapeways is still allowing this at this time, I continue to suspect that it will become a problem for designers when/if they disallow such collections. At worst, we were previously warned.. don't abuse the Part Count.

Thinking of the poor production person, imagine trying to fetch a set of these http://shpws.me/oCRi out of the printer - only 4mm tall - no sprue - no cage. And remember.. they first clean the tray with an airhose!

The best solution is to sprue or cage your models together such that they can be picked up by a human hand as a single PART - that will remove the chances that they mix two similiar items from two different designers or foul up the part count as happened to you this time.

Take a look at this model: http://shpws.me/puwG - very small stuff, but even if an item inside the cage were to go diagonal, it still couldn't get out of the cage.

I see what you mean about size! Looks like you're at the mercy of the tech's train knowledge. As mkroeker said there must have been some failures and reprints in the mix. It'd be worth finding out what parts of the models might have been causing trouble, in case it is something that could be improved for better print reliability? Neat shells - HOn3?

I think I found the canonical ten differences between the first and second locomotive, but it would not surprise me if they looked pretty much the same before cleaning. How many models hide in a typical lump of WSF, and how much time is available for separating and cleaning them, especially now in what is hopefully a holiday rush ?

They are British 009 scale - 4mm scale on 9mm track , roughly the same as HOn30. They're a drop fit on the good runing and cheap Kato 103 chassis.

They are designed as a cheap starter loco - the bodies will retail at around $20, about one third of the next cheapest 3D printed loco.


I was told at one point that thin flexible sprues made getting larger things like this difficult to separate as the rows tended to tangle up causing damage.

Simmerly I've been told that mesh boxes make things hard to clean - I do wish we had some firm advice on this as it seems to keep changing over time.

I must admit I've been a bad boy recently - been removing sprues from some of my smaller items - the changing specifications have meant I have more things being rejected on the size of the sprue than on problems with the size of the object itself. It's been easier to just remove the sprues!

Tom

Really small things are exceedingly hard to find in the powder cake (Strong and Flexible family) and we really do prefer they be sprued together, up to a point. It would be nice if parts smaller than about x+y+z=30mm are sprued together. (if it doesn't destroy your design) This saves use time and headaches of tracking down where all the small parts went when we clean the excess powder from them. This is a two sided tool though. When the sprues get too big and complicated, it becomes more and more likely that something will break off and be over looked and you receive a model with a 'piece' missing. So really the answer on 'to sprue or not to sprue' is: it depends. This is probably why you get different answers over time. I know that it would be awesome if we were able to give a really firm simple answer to this. Please understand that with the infinite variety or parts and models that we make it is really hard to give a simple answer to this.

To answer your original question about splitting orders; we will split a file into 'Shells" to help us pack more into a printer. It is easier to find 30 little spots than 1 big spot. We try really really really really hard to fit whole orders into a single print job though. What probably happened with your order is exactly what mkroeker said, either a printer crashed or a few parts broke in your order and we messed up what got reprinted and apparently forgot how to count to 30. For this, I am profoundly sorry. If you contact Service@shapeways.com they will get this fixed and make sure you get all of the correct parts.

Thanks for that

It's good to have a definitive answer, even if it may not be the final definitive answer!

Just so we are clear is there a size above the x+y+z=30mm you suggest, were spruing things together is useful but not essential, or does it become a liability then. The ones I've been removing the sprues on are around twice that size, I have left all my really small parts on sprues.

As regards the order being wrong, it's not too much of a problem for me, I still have the right number of things to sell and the inconvenience and cost to you is going to be out of proportion to the benefit I will gain - I was more interested in how this happened - even though I don't want a replacement should I let Service@shapeways.com know what happened so you can be more awesome next time ?

Tom

Hmm... A maximum size is going to be very subjective. If I had to make a wild guess, things greater than x+y+z>200mm. This should be taken with a pound of salt as I have not spent much time thinking about it. Instead, I would probably try to use a common sense rule like 'even if I didn't know what this is, would it be obvious that something is missing?' Thoughtful design can be very helpful in this regard. Keeping things symmetric across one plane helps a lot as does having obvious posts where parts are intended to be. If you want to be amazingly nice to post production, throw a bit of text on the sprue saying how many items the are supposed to be.

Hmmm. Despite being a veteran plastic kit builder, I never even thought of putting raised text on a sprue! Now I think of it, that's a great idea - not just for the poor SW tech, but also for customers... (I'm thinking part numbers, etc to match assembly instructions.)

Thanks!

It's been a (long) while, but isn't this how the old plastic kits (Airfix, Revell) used to work? So simple but very clever...

This is the kind of stuff that should be on an official SW page.