Just read an article on the maker of 3-D printer and thingiverse. Some of you engineering types enlighten me please. Since we seem to have a scarcity of right side engine side covers, and the originals seem to have a tendency to crack by the kickstarter boss, could an improved stronger version pattern be made on the copier and used as a casting master pattern ? Looks to me like this would be very do-able and relatively inexpensive. Any one out there who can give a clear answer to this question ?
Mikeyrx
3d printers: questions from the techno-challenged
3d printers: questions from the techno-challenged"a free motorcycle is a bottomless hole intended solely for money"
66 CB 77 76 BMW R75/6 99 GL 1500 trike 75 & 79 XS 650's Mike
Everything is possible. The 'pattern' produced would have to be larger than the original as it has to allow for shrinkage during the casting process. Once you have made a pattern you could use it as a master to make a female mold from which production patterns could be made. Whether you can get away without a multi-part pattern or not requires a little bit of investigation, but its a pretty simple (but large) part. For small volumes you would need to find a foundry that can work with aluminum and get them to cast you a small run of parts. Don't expect this to be cheap as it is quite a large part with thin wall sections. After that comes machining. Not much to do here except for the joint face, a few threads and the clutch adjuster. It is possible to make metal one-offs using a process called selective layer sintering (SLS) that might be more appropriate for this part. http://en.wikipedia.org/wiki/Selective_laser_sintering G '60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F Jensen
Nice! I guess you're using the original part there as the pattern. That's ok with simple parts but the part produced will be smaller than the original. If the part has to it closely to something else that is a problem. Sand casting would still be the preferred method for what I described above. Casting that side cover would be a bit of a challenge. Die casting dies are 10k plus. Investment casting is nice but not so easy for bigger parts. It is a 3000 year old proces invented by the Egyptians. My rail sensors are investment-cast stainless steel. G
Last edited by G-Man on Fri Nov 30, 2012 5:12 pm, edited 1 time in total.
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F
Re:Jensen and G-man: You guys rock ! I knew about the shrinkage factor since one of my friends used to make reproduction Pope bullet molds. I can see some of the problems that would be encountered. I had thought of sand casting but making a master that would produce a proper sized finished piece looked to be a large task. How do you enlarge a complicated piece in 3 dimensions ? You have both given me food for thought. Maybe this should be my next retirement project. Mikeyrx
"a free motorcycle is a bottomless hole intended solely for money"
66 CB 77 76 BMW R75/6 99 GL 1500 trike 75 & 79 XS 650's
Re:I knew about the shrinkage factor because my neighbor is George Castanza. 1965 CA77Dream
I would think that you could have an original part traced using a Faro arm or similar modern tech measuring system. Then, a good engineer could load that into a cad program and knowing the weak points on the parts, modify the design to make it stronger. Then, an experienced casting facility should know how to scale up the measurements to allow for shrinkage as well as add material where machining will later remove it.
I have zero experience in investment casting. But when I was in China during the early years of their recent industrialization, I was given a tour of a factory that was mass producing the valve assemblies that go on oil-well heads. They were pretty complicated stainless castings and were made using the lost wax process. That all said, and others have mentioned this, it won't be cheap and I'm not sure you would sell a lot of these. I have spoken to a gent on another forum who has made replacement parts for another bike and he has yet to sell a single one of either part. I suspect that most are welding up the damaged cases and calling it a day. regards, Rob
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