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Dome blowing on Thermoforming centre

Discussion in 'Design and technology' started by mollys, Jan 11, 2011.

  1. Hi all,
    I've played around with the dome blowing unit on our thermo forming centre but cannot get much over a shallow bubble. Does anyone know this process well? How can I check that the pressure is high enough? I've tried keeping the material warm with a heat gun as I blow as I was concerned it was cooling too quickly but this only slightly improves the outcome.
    I need a nice deep half sphere for one of my A level students.......
    Any help/tips appreciated!
     
  2. re

    re New commenter

    We have a separate dome blower - we use the vacuum former to heat up material and a compessor to blow air into it. It sounds as if you are either are not getting the material howt enough all the way through or do not have enough pressure. Or, ossibly, you have not got a good seal around the edge.
     
  3. I agree, we have a separate blower that runs off the side of the Vacuum former but any leak at all causes low pressure. These blowers do not have a high pressure but work by continuuous low presure so any leak is disasterous. Try blanking off the orifice and looking for leaks.
    I you cannit get it to work why not vacuum form over half a ball filled with something to make it rigid like plaster?
     
  4. Dome blowers are lovely when they work well. However, I have often had to resort to standing on a chair, pressing down on the metal seal bit with a pari of pliers! I've had better success by getting the plastic hotter, so you might want to try that?
     
  5. Thanks for all your suggestions so far. I've checked all the seals, moved the machine into a slightly warmer workshop and aided the dome with a low power heatgun to maintain the 'elastic' stage which has all helped. I am however going to get my maintenence team in to check the pressure level too.
     
  6. If you are still having problems, get in touch with me at rhylhightech@yahoo.co.uk and i can either do one for you or get someone at CR Clarkes to possible do one. Where is the school you are teaching at as i might be able if its not too far to come and look.
     
  7. Maintenence team called in on Thursday and replaced the seal with a brand new 'donut' and the results are much better.
    Thanks for the kind offer though - its good to know how supportive everyone on here is ;o)
     

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