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Awesome. Ill have a look
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Bart Risuccia |
#32
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Oskash I assume you got there.
Did you see the Hamilton Metalplane, one of the very earliest parts of what would become the Boeing corporation.
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Fred26T |
#33
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Thank you,
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
#34
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"a few itinerant metal bipeds "
Kent, we got to meet sooner or later!
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Will |
#35
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No, I missed Osh this year - and all of the displays. Is the Metalplane this one..... http://www.barrett-jackson.com/Media...on-scottsdale/ ?? Had not heard about the TriMotor sale..... sheesh.
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
#36
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I have a question regarding suitable plastics for flow forming.
Material is 1mm mild steel CR4. I am using a 5x gun with an acetal insert. The hammer form is steel, 600mm long bead approx 50mm wide, ends are 25mm radius. Workpiece is 600 x 850. I decided to flow form because I am not proficient at using the Pullmax and was worried I could not correct distortion if I didn't use a clamp plate. The issue is that I get puckers, like a rib effect,on the sides of the bead - I.e the sections of the bead at 45 degrees. I think this is from the insert contacting this area, which is unintentional but I can't see how to avoid it. I have tried different dia inserts, wider help but still I get occasional rib effect. So I tried some polypropylene which is less hard, but still doesn't mitigate the problem completely. My question is what material should I try next? I feel the gun is over specd in a way, I would sacrifice a slow forming capability for a cleaner result. Only prerequisite is it Needs to be machinable so I can put it into my attachment on the gun. Or is it unavoidable? Appreciate all your suggestions. Thank you Will
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Will |
#37
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I'll try to help you: When I got started in this (1980 or so) I took what the guys at CalMetal (Calif. Metal Shaping) were using and went on awhile with that stuff. "Okay" stuff. After a number of years of trying various off-the-shelf materials of all sorts, I went to plastics companies and asked them what they had for sustained impact on metal and and tried what they recommended - with varying "okay" results. I even vulcanized my own rubber, with my own molds, under pressure, with timers and thermo-controls. "Okay" results. The car guys in Detriot have some plastics that they really like, so I foraged through that list, with "okay" results. I now use urethanes patented by some end users because of the design of their urethanes for sustained impact - like motor mounts, suspension components, etc. If you have access to a Plastics Mart or something similar, ask them for what is current tech for stuff that takes repeated impact. (UHMW goes weird when I use it. Delrin explodes. etc. etc. This forming process can be hard on tools and materials...) http://www.tinmantech.com/html/flow_forming_inserts.php Hope this helps,
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
#38
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tool inserts
Will,
P1010049 copy.jpg Here are some of my inserts. Some are machinable, others are best cut after chilling with liquid nitrogen. Aluminum, brass, bronze and steel are good metal inserts that can be machined - knowing you asked about plastics.
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
#39
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Thanks Kent for your reply. I will keep playing about with different materials.
Quote:
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Will |
#40
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Smoking acetal releases formaldehyde IIRC
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Marc |
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