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| shipto:
I hope someone can give me some ideas. I am making a tool to fold plastic sheet 3mm - 4.5mm into tubes for work. Currently the guys who do this stuff fold it around by hand and I have the job of making it easier for them. I have made a jig that means they only have to bend a semi circle by hand and then the tool will aid them to bring the two ends together for welding. now currently they use a bit of 30 X 30 box clamped either side to hold the plastic down this has a problem however in that the plastic pushes up in the middle meaning you do not get a perfectly flat welding surface. so i need a way to clamp at least 1200mm long nice and flat but it has to be totally removable to allow the welded tube to be taken out afterwards. any ideas you can throw my way would be helpful. |
| PeterE:
Just to start the ideas .... This sounds like a 1200 mm long pipe with the said inner diameter split along its centerline and equipped with a "piano hinge". This will make the pipe open and close nicely. Pinching can simply be done using the locking kind of welding pliers. This contraption will hold the tube to be along its length and nicely squeezed to its round shape, but will it work???? Well as said, just an idea. BR /Peter |
| shipto:
--- Quote from: PeterE on February 16, 2012, 04:08:12 PM ---Just to start the ideas .... This sounds like a 1200 mm long pipe with the said inner diameter split along its centerline and equipped with a "piano hinge". This will make the pipe open and close nicely. Pinching can simply be done using the locking kind of welding pliers. This contraption will hold the tube to be along its length and nicely squeezed to its round shape, but will it work???? Well as said, just an idea. BR /Peter --- End quote --- Unfortunatly no I have already thought of something similar the problem lies in that the tubes they are making can be anything from say 1000mm diameter to 250mm the big diameters are not that hard to make and require two sheets of plastic hence two welds down the length the smaller diameters take a lot of folding and plastic unlike sheet steel will not stay round if you roll it. It is moulded/extruded whatever, flat and it wants to stay that way. keep them coming however. |
| 75Plus:
I can visualize a device that should do this job but I can't get my head around how to sketch it up. Perhaps I can draw a word picture. Start with 4 pieces of angle iron to clamp the edges of the material. Placing a slight bend in the AI will increase the grip near the center. Now make a bit to attach the ends of one set of the AI clamps to a set swing arms the length of which is half the diameter of the desired tube. Attach the other set of AI clamps to similar arms. With the ends of the swing arms secured so they can pivot they should bring the two edges together. The device used to connect the clamps to the swing arms must be free to pivot in order to align the edges for welding. Once the welding is done the AI clamps can be removed. Hope this makes sense. Joe |
| shipto:
--- Quote from: 75Plus on February 16, 2012, 05:18:39 PM ---I can visualize a device that should do this job but I can't get my head around how to sketch it up. Perhaps I can draw a word picture. Start with 4 pieces of angle iron to clamp the edges of the material. Placing a slight bend in the AI will increase the grip near the center. Now make a bit to attach the ends of one set of the AI clamps to a set swing arms the length of which is half the diameter of the desired tube. Attach the other set of AI clamps to similar arms. With the ends of the swing arms secured so they can pivot they should bring the two edges together. The device used to connect the clamps to the swing arms must be free to pivot in order to align the edges for welding. Once the welding is done the AI clamps can be removed. Hope this makes sense. Joe --- End quote --- Not understanding 100% I have thought about a slightly curved clamp however so the middle will contact before the ends do. think it might work if I do not put too much curve so that it isnt too hard to use. |
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