Thought I'd throw this teaser out here. Since Red97 was looking for a casting that was very close to the experimental part I made here: http://forums.thehomefoundry.org/index.php?threads/high-aspect-ratio-features-and-deep-draws.13/ I thought it was a good opportunity to put lost foam to the test on a real life part. I did take pictures and some videos along the way, so will be able to post those up in time. Best, Kelly
Here’s a series of short videos on machining each of the piece parts. First off, the first two machining operations of upper portion of the cylinder Next machining the fins onto the same part Next up the cylinder head. Next the cylinder base Best, Kelly
Next the intake and exhaust port tunnels Now I didn’t take video but there is an operation that holds the cylinder at the entry angle for each intake and exhaust port while the cylinder is machined to receive each part. Here’s a picture of that fixture: …..and a group photo of most of the jigs. …..and finally a couple pictures of the assembly detailed up and ready to be sprued, coated and cast. Best, Kelly
Thanks Mr. Ed. Sometimes necessity can be the mother of invention. It's decidedly low tech, and certainly some design compromises made for (my version of) the Lost Foam pattern making, but once some simple jigs are made, duplicate patterns come fairly easily. We'll see how these cast up. I may add some porting details on the batch of patterns in the videos. The original head is a pressure die cast part. The fins are very thin.......probably .040-050" at the tip. You could get more detail by printing PLA and investing it but still think you have to make some design changes to get it to cast. Best, Kelly
Thank you for taking the time to document the process. Those patterns are very nice and should do everything I need. Is the fillet material a wax product?
You're welcome. Still gotta make'em metal pal but I think we'll get there. Yes. I use it sparingly for detailing fillets and joints that can't practically be machined into the foam. Without it, the pattern coating can penetrate the small gaps and the resulting hairline cracks at the interface will cast through making worse stress risers than just a sharp corner. Small embossments, part numbers etc are possible too. These are the smallest I can apply." Still needs a little clean up here and there. Best, Kelly
Kelly when are you going to ditch that drywall mud and use shell? Do I need to send you a BP too? You won't be dumping aluminum on your foam. You fire the shelled foam. Foam evaporates cleanly and in goes the aluminum. Your neighbors will thank ME for eliminating your obnoxious black soot.
Next thing is to figure a way for high a silicon alloy around the bore... Like the old Vega blocks lol Then I wouldn't have to worry about an iron liner, or sending them out to be plated.
Think we've had this discussion before Jason but the short answer in this case is because shell only adds additional labor and substantial process time with no benefit to the part produced......and shell burn out of foam still stinks and persists longer than the 15 seconds or so of a lost foam pour. Best, Kelly
After it's cast I would contend the next thing is for you to take a pause from burning wire onto 200,000lb steel castings long enough to machine the casting and run it! Best, Kelly
Touché.. Have about 2k of wire burned about 13k to go. I may be able to have the machine shop here draw up a program, and finish the casting while I'm burning wire. Otherwise it will be a bit before i make it home to finish it my self. Don't think the customer will see the importance of pausing their project to do mine.
That's the life of a self-employed man......just as long as you concede to being outdistanced by another self-employed guy twice your age.... Best, Kelly
