Finally getting down to business with sketchup

[Hauk]

Lately, I have been spending far too much time using Sketchup at work, and far too less for modelling.
But finally I have made a modest start on the hardware for a Ore car in 0-scale.

Here are some pictures of the prototype (slightly different ones):




I am not sure how I will model it, I think I will make a resin casting of the body, and an underframe made of brass profiles and custom etched fittings.

But I have also ben contemplating making some brass castings for the body hardware.

Either way, I plan to 3D print a lot of the parts, so I just have to get on with the SU modelling.

Here is the first part:



It is not a mistake that the bolt has an indent (dimple?) instead of a "bolt" sticking out, the plan is that the casting will be drilled through the bolt so a  thin wire can be inserted to connect another part to this one.

One thing I a uncertain about is that some of the hexnuts seems to lack contours. Can this be a source of problem? They are made by drawing a circle with just 6 sides, and then lifted with the "Push/pull" tool.

Maybe not to much to comment on, but any input is most welcome!

Regards, Håvard H

[eTraxx]

I see that this will allow that part to connect to the .. support bracket? Door arm? Seems if you did the same on the upper hinge then you could make the door operable ...

[marc_reusser]

Very neat subject, and nice work so far on the drawings and planning. Nice to see you diving into this. Look forward to your progress and results.

In regards to the bolt/circle issue....just curious why you are using the 'circle' tool for this instead of the 'polygon' tool. I don't know if using the circle tool will make any difference when it is read/converted and surfaced for an STL. as the converters merely read surfaces/facets.....but looking at the one bolt in the last image, it seems to have softened the transition to adj. surfaces....which could be because you used the circle tool rather than the poly (being that the circle overridingly is meant to transition from plane to plane, whereas a poly isn't.)...during the STL conversion this will usually be recalculated as a straight facet transition....but I am thinking of an off chance where this could really increase your STL file size, because deep down it is still registering these as more complex circles rather than simple-plane poly's.

....just a wild-ass bunch of assumptions on my part.


Marc

[Hauk]

I see that this will allow that part to connect to the .. support bracket? Door arm? Seems if you did the same on the upper hinge then you could make the door operable ...

A valid point. If I am going to make this part in brass, I would do that. In resin, I think the connection will be far too fragile.
But I wonder if it is possible to cast such a long, thin part in brass. It is just 0,3mm thick.

If I cast this part in brass, It will be as hardware for a body made of stripwood. I would then make some of the bolts with "dimples", so that I can drill through them and pin the part to the wooden body with thin brass wire.



Regards, Håvard H

[Hauk]

In regards to the bolt/circle issue....just curious why you are using the 'circle' tool for this instead of the 'polygon' tool.

Marc

Another good point! I have no idea why I havent discovered the polygon tool. I felt quite clever using the circle tool...

And thanks for the input. Where else than on this forum do you get constructive comments just *minutes* after posting?
This place is just the best.

Regards, Håvard H

[finescalerr]

Here is a similar car I designed some years ago. An engineer went over it to ensure it would hold together but a fellow modeler noticed the hinge design might foul. I had planned to make styrene masters and cast resin parts. Those were the days before stereo lithography and laser cutters. -- Russ

[Hauk]

Some progress. The body is almost finished:





The assembly is for the photo, I will print the sides flat as individual parts. Then I will get away with two masters only 2,5mm high.

But I really wonder how they will turn out in print. For instance, will the grooves between the boards show? Or become too prominent?
I am also wondering if i should make triangular or square grooves. I have tried 0,1mm X 0,1 mm square grooves and triangular grooves with 0,3 mm sides. Input is welcome!

-Håvard

[marc_reusser]

Hauk,

Looking great.

The grooves will show when printed.  By no means in any form am I an expert, Chuck could probably offer more input, but FWIW, here are few thoughts based on my very limited experience so far:

If you print the surfaces flat (the grooved exterior side facing upwards) you should have much less large syrface clean-up than if you print the sides vertical. (I noticed on my prints that the top and bottom surfaces had less printing texture...at times even completelu smooth.)  this means you would possibly have to do stack the sides, with sprue posts between them supporting the pieces...these small spots would need to be cleaned-up/sanded in the end. By stacing the sides, you also reduce the printing footprint, thus redicing cost (since part of charge/cost is the sq. area your printed item occupies.

Re. the grooves....Either one will show.....you just need to conseder which shape will be easier to do a crisp sanding clean-up in, without rounding over the corners/edges....personally I would probably choose the 'V', and then make a shaped piece/sanding-block to fit the sandpaper overso that it fits neatly in the groove (this piece could be printed with PAP as well ).

I am a bit concerned that the bolts will be too much detail and to small to get a good cleanup on (not to mention the time and effort needed to do so)...because crooked or oversanding would really show on this type of detail.....I would probably go the route Chuck did with some of his small details, and do dimples..or just complete holes (depending on how you like to install NBW's) at those locations and then use styrene NBW's from Grandt or Tichy...or whomever you prefer.

...anyhow...just some thoughts.

Whatever way you go, it will be a great learning experience for us all. Thanks for doing this.



Marc

[Hauk]

Thanks for the feedback, Marc!

I have not decided yet where to print the parts, but it is possible that the parts will be printed on a Solidscape printer.
I hope that with the resolution of the Solidscape printer, no cleanup will be neccesary.  If cleanup is needed, I agree that it will be virtually imposible to clean up all the bolt detail.

A friend of mine runs a small model company, and he places order for batch runs on a Soildscape printer every now and then. I guess one side and one end will be around USD 100 if I can join him on one of those runs.

But wax parts are really more suited for a lost wax casting production chain, and not a resin route as I am leaning towards. But I have heard that some people have made RTV silicone masters from wax parts, anyone here with experience on that?

My friend never actually sees his wax parts by the way, he gets his wax parts made by a jeweller, and he delivers masters in metal. For convinience, he often does the masters in pure silver!

But I am not sure if US 100 will cover the metal masters as well. You could of course make RTV moulds from metal masters. With metal masters it would be easier to assemble a complete body before making the mould, but then you would of course need  to print two sets of ends and sides, as you can make only one metal part from each of the wax prints.

I am also seriously considering casting all the parts in brass. It is possible that this will be cheaper than casting 50 bodies in resin. You would then have to solder up each body from 6 brass parts, but with some clever wooden jigs I think that will be pretty straight forward. Two things to consider though; weight of the finished car, and will the sides and ends be flat enough when casted in brass?

Two sum up:
1. My 3D parts will be used as masters.
2. The 3D parts should need no cleanup
3. From the masters, I need castings for at least 50 bodies.
4. The finished parts will be cast in brass or resin.
5. Resin bodies could be cast as  one piece.
6.Cast in brass the bodies will be assembled from 6 parts (sides, ends and bottoms).
7. With brass part, working side doors is a possibillity, but it will require a separate print (and part) for the door.
7. Cost is really not that important, as this is a project that will span several years, and some of the cost could be covered by selling a few finished cars.

Lots of things to consider, but to me all this tinkering is half the fun!
Please keep the comments coming!

Regards, Håvard

[Hauk]

OK, after some tweaking and colorful language, som .stl files have been made:





If anyone would like to take a look at the .stl files, they can be downloaded here:

http://www.folk-rovere.org/mj/bilder/Ende_test.stl
http://www.folk-rovere.org/mj/bilder/Side_test.stl

If somebody has comments on the integrety of thos files, cry out!

I made them by exporting .dwg files from SU, and Importing them in Vectorworks, and exportin from VW as .stl.
It would make more sense to export directly from SU to .stl, but my SU .stl xport plugins aint wotking for some reason. So I use what I have available.

Uploaded tem to Print-A-part to get a price just for the heck of it, do not really think I will use PAP.
Got a quote for the side at $20 (63mmX31mmX2,5mm), and $18 or the end (51mmX31mmX2,2mm) 

-Håvard

[Hauk]

Just to take things a bit further, I uploaded one of my parts to PAP and ordered a print as a test.
It seems PAP accepted the part, but when I checked the file with Mini Magics, it seems that it is seriously flawed with multiple bad edges and reversed faces.

Can PAP stilll use the file? And those of you that has tested PAP, did you test the files prior to uploading?

Regards, Håvard

[davej]

http://www.folk-rovere.org/mj/bilder/Ende_test.stl
http://www.folk-rovere.org/mj/bilder/Side_test.stl

If somebody has comments on the integrety of thos files, cry out!

I imported them into Solidworks are the files didn't show any errors.

What width have you used on the board gaps? I have all my parts printed on a Solidscape machine and have tried some V shaped fine grooves 0.15mm wide - these didn't reproduce well. A square bottom groove works better.


d

[marc_reusser]

Just to take things a bit further, I uploaded one of my parts to PAP and ordered a print as a test.
It seems PAP accepted the part, but when I checked the file with Mini Magics, it seems that it is seriously flawed with multiple bad edges and reversed faces.

Can PAP stilll use the file? And those of you that has tested PAP, did you test the files prior to uploading?

Regards, Håvard

Havard,

If PAP accepts it after their "check", then they should be printable without any problems. You will note on the PAP check page that there is something called "gap fill setting" or some such thing (not looking at the page at the moment)....maybe their use of this is what helps the part not show problems.

If you have reversed faces, some check programs will potentially read them as holes (don't ask me why..I havent a clue)

RE. orienting the part faces in SU......if you select the entire component (or all the parts by dragging across), then right click, you will see a command "Orient Faces"....this should orient all the faces in the same direction...now that may be all inside or all outside...depending on how the program handles it.....if they all oriented to the "interior face" (darker color showing, then, before deselecting the items, right click again, and select "reverse faces" this will reverse all the previously oriented faces so that the other side shows.

HTH.

Marc

[Hauk]

I imported them into Solidworks are the files didn't show any errors.

What width have you used on the board gaps? I have all my parts printed on a Solidscape machine and have tried some V shaped fine grooves 0.15mm wide - these didn't reproduce well. A square bottom groove works better.

Thanks a lot for checking the files!
I was a bit worried as I got error messages in MiniMagics an MeshLab.

As for the grooves, The v-shaped ones are 0,3 mm deep and wide. I also have some square grooves that are 0,1 by 0,1.

Guess I have to wait for the PAP test part for the final verdict.

-Håvard

[Hauk]

Just got word from PAP that my test part printed without problems.
I was a bit worried as I got error messages in MiniMagics and MeshLab. Speaking of MiniMagics, have anybody managed to get a part other than the most basic shape to validiate as error free in this software? Whatever I do, I get error messages in that program. Also on the file that PAP and others found no fault with.

Regards, Havard