DIY 3D Printing

[Lemosteam]

Keep in mind yours is not the only model in the vat.  They could have placed 20 parts above your shell requiring wax along the side of your model all the way up to the top.  The vat "bounding box" as they call it is 50mm wide  x 50mm tall  x 200mm long for FXD.  For FUD it is 284mm x 184mm x 203mm.   So if your print was on the bottom of the vat then anything could have been above it.  I suspect the good one in your pic was at the top of the pile and everybody else got the fuzzy treatment.

[BCR751]

I have asked the designer if the shell  is available in another medium like FXD OR ABS. If the printing vats are smaller for those maybe that would result in a cleaner print.

Doug

[peteski]

I have asked the designer if the shell  is available in another medium like FXD OR ABS. If the printing vats are smaller for those maybe that would result in a cleaner print.

Doug

Doug your "good" example looks as good as the Kato RDCs (at least it does in that photo).  The "bad" example looks like what I normally expect to see from a FUD-printed items.

I don't think there is a printer out there within reach of a hobbyist (price-wise) which would be able to print with the quality and resolution you are seeking.

@Lemosteam John, you mentioned a vat. I think ProJet printers used for FUD and FXD printing don't print the parts in a vat of liquid resin. They work like ink jet printers, squirting resin or wax as needed  from the their print-heads.  I found a video whcih as short snippets of the printing process. Looks like the resin might be cured by UV light but not in a vat.

That video is on this web page.

[BCR751]

So, I guess its a crap shoot as to whether one will get a decent model from the 3D process, especially one with fluted sides.  I did manage to contact the designer and he said he may be able to request how the model is oriented so that could help.  But, again, if he is overridden by Shapeways, which I understand is a possibility, I would still get a crappy shell.  He requested photos so I'll send him the ones I posted here.

In an effort to salvage the shell I have now, I'm going to go over the whole thing with a brass wire brush in an effort to get rid of some, or all, of the fuzz and then hit it with successive coats of the silver paint and see if I can get looking at least presentable.  Not sure what else I can do in this situation.  Any suggestions are most welcome.

Doug

[peteski]

Because the way fluting is shaped, there is no way to avoid the wax supports in the areas.  Well, maybe if the model was printed standing on end. But if some detail higher up on the model was protruding beyond the fluting surface, then a wax support would be built up against the fluting all the way up to where that detail is.

The printing is done from the bottom up. If you were to imagine the model the way it will be printed, then shine a light above the model then any areas casting shadow on the model itself or on the surface the model is sitting on will will be printed as wax supports. If those supports are directly against the resin printed surfaces, those resin areas will be fuzzy.

[BCR751]

I think the shell that looks the best was indeed printed with it standing on end.  If I could be sure that it would be done that way again, I'd order a new one.  Unfortunately, from what I'm hearing, that may not be the case.  I sent the designer those photos and I'll wait to see what he thinks.

Doug

[peteski]

I think the shell that looks the best was indeed printed with it standing on end.  If I could be sure that it would be done that way again, I'd order a new one.  Unfortunately, from what I'm hearing, that may not be the case.  I sent the designer those photos and I'll wait to see what he thinks.

Doug

If it was printed on end then one of the ends should be fuzzy (except for a feature which sicks out the farthest, which would have been resting against the smooth printing platform) would have been fuzzy (as wax would have been supporting all the surfaces of that end.  But the other (top) end would have been really smooth and free of any wax.  Te interior of that shell would have been all fuzzy (as it would have been filled with wax for supporting the top end.

Tub-shaped objects are usually printed upside down to minimize use of the wax.  That results in the inside of the roof, and the majority of the interios surfaces being smooth. The outside of the roof is then fuzzy.  But that is not the optimal orientation for the modeler where we we don't care about the interior surfaces and want the exterior surfaces to be as smooth as possible.

If you examine any FUD or FXD 3D-printed object you can determine its print orientation by observing the surface finish and following those fuzzy clues. 

[Lemosteam]

Doug your "good" example looks as good as the Kato RDCs (at least it does in that photo).  The "bad" example looks like what I normally expect to see from a FUD-printed items.

I don't think there is a printer out there within reach of a hobbyist (price-wise) which would be able to print with the quality and resolution you are seeking.

@Lemosteam John, you mentioned a vat. I think ProJet printers used for FUD and FXD printing don't print the parts in a vat of liquid resin. They work like ink jet printers, squirting resin or wax as needed  from the their print-heads.  I found a video whcih as short snippets of the printing process. Looks like the resin might be cured by UV light but not in a vat.

That video is on this web page.

By vat, I simply meant the space where the material is printed, also why I quoted the Shapeways terminology for that space. 

[Dave Schneider]

It is frustrating that the ability of designers to render outstanding 3D models has grown much faster than the ability to 3D print them. I used to make a similar joke about big screen TVs. They got bigger much quicker than my ability to convince my wife that I needed one.

Best wishes, Dave

[wcfn100]

It is frustrating that the ability of designers to render outstanding 3D models has grown much faster than the ability to 3D print them.

On top of that are all the promises of affordable home SLA printers that just never seemed to happen.  Then HP announced they were getting into 3D printing but only large business printers so far. 


Jason

[Mark W]

...They could have placed 20 parts above your shell requiring wax along the side of your model all the way up to the top...

Just want to point out the myth in this.  Despite the name, 'Rapid prototyping'(3D printing) is quite a time consuming process.  It takes a machine several minutes per layer, just for a tray/vat size of a a few square inches.  For FXD, each of those layers is just 16 microns, or 6/10,000ths of an inch.  The amount of material, and more importantly, the amount of time it would consume to print a vertical buffer between different items  is just not economical. 

Instead, they'll group items from their product queue by height.  So even if the machine can print 100mm vertically, it's much faster/cheaper to print 3 runs of various items grouped in 10, 14, and 8mm high trays than one run of a 34mm + 2 vertical buffers.

[Chris333]

Someone showed me a 3D printed O scale window frame and tankcar dome with no banding and it was a slightly flexible material. Almost like nylon. All I heard was he got $1000 off for buying a used machine with little run time.

It used liquid resin that hardened with a laser. A liter of resin was $110.

[peteski]

Just want to point out the myth in this.  Despite the name, 'Rapid prototyping'(3D printing) is quite a time consuming process.  It takes a machine several minutes per layer, just for a tray/vat size of a a few square inches.  For FXD, each of those layers is just 16 microns, or 6/10,000ths of an inch.  The amount of material, and more importantly, the amount of time it would consume to print a vertical buffer between different items  is just not economical. 

Instead, they'll group items from their product queue by height.  So even if the machine can print 100mm vertically, it's much faster/cheaper to print 3 runs of various items grouped in 10, 14, and 8mm high trays than one run of a 34mm + 2 vertical buffers.

Well, that seems to confirm my speculations: In all the items I had printed in FUD and FXD I have never seen any telltale signs of wax supports for other items which would have been printed above my parts. Only the wax supports I can attribute to the orientation of my parts and any overhangs in my parts.

[Lemosteam]

Just want to point out the myth in this.  Despite the name, 'Rapid prototyping'(3D printing) is quite a time consuming process.  It takes a machine several minutes per layer, just for a tray/vat size of a a few square inches.  For FXD, each of those layers is just 16 microns, or 6/10,000ths of an inch.  The amount of material, and more importantly, the amount of time it would consume to print a vertical buffer between different items  is just not economical. 

Instead, they'll group items from their product queue by height.  So even if the machine can print 100mm vertically, it's much faster/cheaper to print 3 runs of various items grouped in 10, 14, and 8mm high trays than one run of a 34mm + 2 vertical buffers.

Good point @Mark W , but that does not PREVENT them from doing it, so it's not really a myth.  Doesn't economy depend on how many machines they have running and how busy things are?  Plus there is the evidence above, SOMETHING messed up the sides of that car and we already know the the first car could only have been printed vertically in FUD but not FXD (50mm vertical limit).  Only other thing I can think of is they printed that car on ond sideand the initial support layer messed it up.

@BCR751 Is the other side of that car just as bad?

Here is an image of one of my models that I send in- I don't think they can move or separate the parts at all, note that the seats are directly below the roof:



Here is how they looked after printing:

[Lemosteam]

Someone showed me a 3D printed O scale window frame and tankcar dome with no banding and it was a slightly flexible material. Almost like nylon. All I heard was he got $1000 off for buying a used machine with little run time.

It used liquid resin that hardened with a laser. A liter of resin was $110.

What was the brand of the machine?