Jump to content
 

Printing Domes and Chimney for L& Y Rail Motor


Recommended Posts

Hi there

 

I am in the process of building a Jidenco L&Y Rail Motor as part of the fun I have no suitable Boiler fittings for it such as a Chimney and Dome. So I have decided to get some printed up using Shapeways using Google Sketch up to draw them. I have started to draw the required dome as you can see in the screen shot below. The problem I am having is how to produce what I would call the fillet/radius/flange where the dome meets the boiler. At present my attempts are either leaving a gap between the fillet/radius/flange and the side of the dome or boiler depending on which line I use with the follow me tool. Of course once I have produced a reasonable fillet/radius/flange I will delete the boiler which is only there for construction purposes. Any clues  as how to draw up a satisfactory dome would be greatly appreciated. Thanks in advance.

post-16182-0-85467600-1404683988_thumb.jpg

Link to post
Share on other sites

Part of the problem is that the required fillet is not a 90 degree arc, except at the very top of the boiler. At points lower down on the boiler, the required arc will be somewhat less than 90 degrees.

Also, you will have to allow for the minimum thickness achievable by the 3D printing process, so the edge of the fillet will have to have a finite thickness.

I use Rhino so I can't help with specific commands or techniques for SketchUp. Rhino can generate a surface bounded by a series of curves. In Rhino, I would try drawing arcs to represent the required fillet shape at a number of points on the fillet, then draw surfaces based on these arcs and the desired intersection with the dome and boiler. It would only be necessary to draw one quarter of the fillet as the other three quarters could be done by mirroring. Maybe 3 or 4 segments (surfaces) would be sufficient to draw one quarter of the fillet.

 

I just fired up my PC and Rhino can automatically generate a fillet at a desired radius between two cylindrical objects, as per screenshot below.  The possible downside of this approach is that the fillet may appear smaller at the points lower down on the boiler, where the surfaces intersect at an angle of less than 90 degrees.  If this is a problem, then the segmented approach may work better.

post-17456-0-28499400-1404744869_thumb.jpg

Link to post
Share on other sites

Thanks Marbel and Rabs for your helpful replys as you can see I have managed to draw a dome which looks right and believe me that was fun not. However the plugin  recommended by Rabs was able to produce the fillet I required. Now having got this far the next problem is that it is not water tight when tested in Accutrans and as I think you will notice from the following screen shot there is a lot of holes so to speak so does any one know of a suitable plugin for sketch up 2014 or program pref freeware which will clean this up and so make it printable.

post-16182-0-16017300-1404850711_thumb.jpg

Link to post
Share on other sites

If you can produce an STL, then NetFabb should be able to fix minor defects. There is a free version available for installation on your PC or a cloud version. I use both. I find the cloud version is better for checking and correcting STL files and the installed version is useful for rotating or scaling STLs.

Link to post
Share on other sites

SUSolid will probably fix that, it's paid but not expensive.

However, it would be better to cure the problem at the source, rather than treat the symptoms.  I suggest that you try different settings for the fillet step.  Perhaps make the surfaces to be filleted much larger and then crop them down after the fillet has been made?

I'm guessing but I think that part of the issue is that the fillet width you have specified is larger than the width of the flange - so it gets in a mess.

Link to post
Share on other sites

I have at last now managed to produce a Dome which is water tight. Regarding making the surfaces much larger and then cropping down that is exactly what I did and I still had problems with water tightness. I am guessing this is down to my limitations as a Sketch Up user and also possibly sketch up it self . Also the required dome shape is a very complex one with a fillet between 2 curved surfaces. Any way using Net Fabb I managed to get a water tight model. In contrast the Jack I have drawn no such problems as compared to the dome it is simple geometry.

So next I am going to draw up the chimney's I will keep you up to date as regarding progress and also thanks for the help and advice given so far.

 

post-16182-0-07804500-1404985800_thumb.jpg

post-16182-0-64231300-1404985816_thumb.jpg

Link to post
Share on other sites

I have now managed to produce drawings for the original narrow chimney and the later more common wide chimney. For the fillet however I had to use curviloft to get something looking half decent roundcorner for this application just could not produce a  decent result in fact it produced some strange results to say the least however I will admit I was using for a purpose I don't think it was intended for. Roundcorner just about works for producing the dome fillet but does need cleaning up afterwards. In contrast curviloft managed to produce the fillet on the narrow chimney and was still water tight whilst for the wide chimney just a little bit of  netfab cloud sorted it out. Now on to the safety valves

post-16182-0-02760300-1405262070_thumb.jpg

post-16182-0-36877000-1405262087_thumb.jpg

Link to post
Share on other sites

Looks excellent, and good to see the problem has been overcome.

Now, going off topic slightly, how did you create the lines around the dome and 'boiler' in the first pic? I'm struggling to think of how you projected the circle onto a curved surface, and onto the dome as well.

Link to post
Share on other sites

I have now drawn up the inside tanks and put all the boiler fittings on to a sprue with all the components enclosed within a box that had 2 of the dimensions 60mm x 30mm this way when I up loaded the design to Shapeways I could easily see if it was to the correct size. Regarding the boiler fittings I have produced 2 versions of it as the first versions Shapeways said there was an issue with wall thickness so I used there correction tool and produced a 2nd version my plan being to print off both in FUD with the 2nd version as an insurance policy.

The next question is as I will be producing these items in FUD what is the best way of cleaning them prior to use , a suitable glue to fix them to a brass surface and would Halfords Plastic primer be suitable my plan would be before fixing to the model prime with plastic Primer and then after fixing prime the whole of the model with std Halfords Primer so in effect the FUD parts would have 2 coats of primer.

post-16182-0-31422600-1405848761_thumb.jpg

post-16182-0-90485500-1405848771_thumb.jpg

post-16182-0-35836700-1405848821_thumb.jpg

Link to post
Share on other sites

  • RMweb Premium

The two parts you have sticking out at right angles would be better off aligned the the same way as the others, ie all parts in a line attached to the sprue. It will make it easier to print, and protect them during transit.

Link to post
Share on other sites

Fair point Nile however at the time it seemed like a good idea as the minimum envelope is 12 mm x 12 mm x 12 mm so as I knew the exact height of the jacks I positioned them to not only go over 12 mm in one axis but why not print off some more plus giving me another reference dimension which I can easy check when uploading to Shapeways.. Anyway when I get the prints from Shapeways we will find out how they turn out.

Link to post
Share on other sites

Hi there Quarryscapes I have had a search back and nothing has turned up any clues say topic subject and roughly when you posted it.

Anyway today my prints arrived and I am very pleased with the results. So I am going to clean them up with white sprit followed by washing with hot as I can stand water and washing up liquid 4 times just to be on the safe side. Leave to dry for 24 hours then prime the to be exposed surfaces with Halfords Plastic Primer again leave for 24 hours and then fix on to my rail motor using super glue.

I will keep you posted as to my progress and I can not at the moment spot any difference between the Shapeways modified Boiler fittings and the original version they both seem to have come out well.

post-16182-0-47880800-1406648371_thumb.jpg

post-16182-0-56033700-1406648408_thumb.jpg

Link to post
Share on other sites

All being well in the very near future I plan to have them for sale via Shapeways however I will first have to set up a shop on the Shapeways site. When I do I will if it is ok with the forum rules let you know.

Anyway I have cleaned and plastic primed the parts and done a trial fit of the Chimney and dome to the Railmotor. Within a few days I should have all the Shapeways details fitted as well as all the other little jobs that all ways take ages to do.

post-16182-0-91506700-1406750172_thumb.jpg

post-16182-0-49727800-1406750176_thumb.jpg

Link to post
Share on other sites

I have now started to paint the Rail Motor and have nearly finished the basic painting of the locomotive body once this is done I will then varnish it ready to apply the L&Y Lining this will be fun outer red then 2 inner white lines!! Anyway the paint which is either Humbrol or Phoenix Precision seems to be adhering well to the printed parts even though I gave the assemble model a coating of normal Halfords Primer.

Also I have now set up my shop on the Shapeways site and I have produced a design of just the locomotive jacks 12 in all if anyone wants to use them on other L&Y and other projects. The link is www.shapeways.com/shops/tuebrooktrains

 

Note for the boiler fittings there are 2 choices the one which has Shapeways Modified has slightly thicker flanges on the bases of the domes and chimneys even though when I got them I could not see the difference.

post-16182-0-44091400-1407573151_thumb.jpg

post-16182-0-11099500-1407573193_thumb.jpg

post-16182-0-23117900-1407573196_thumb.jpg

post-16182-0-98717800-1407573199_thumb.jpg

Link to post
Share on other sites

Glad you like the jacks. Regarding the Shapeways adjustments as far as I can tell there is no noticeable difference between the non Shapeways adjusted versions of the boiler fittings and the adjusted ones and they do not appear to be nobbly.

Link to post
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...