Suitable Replacement for Ultrasonic Plastic Welding

I would break this up into 2 operations....I would cut the plastic into 2 pieces, weld the bag to the one piece and then the plastic part 1 to plastic part 2....this strategy would allow access...The hard plastic would have to be split strategically to allow this to work...

Instead of weld, I would make a thread on green PC. And tightened the LDPE transparent bag with an external threaded ring on green part.

Have you looked at bag sealing technology?

Maybe speak directly to some about your problem.

PAC MACHINERY

• PACKAGING AIDS
• VERTROD
• CLAMCO
• CONVERTING TECHNOLOGY

1 (234) 222-1000

Is it possible to make the rim on the cap tapered so that tolerances in the bag could be compensated by pushing the bag further onto the rim? Then your existing welding procedure would produce reliable results.

Forget a hot wire - it cuts through the bag before any welding occurs

You could make a set up that works.

Make a lint of thin stainless steel - as you can recover from a windscreen wiper base. You can heat this up with a low voltage transformer and a voltage regulator.

For packing machine heaters a flexible - self sticking Teflon tape is available.

The principle is that you need to heat BOTH plastics, without melting the bag prematurely - here is the Teflon coming into play- part of the lint needs to be isolated so

that your bag withstands the heat and pressure.

The lint has to be strapped around the ring and bag with some pressure (a mini vise grip with isolated tips can do this

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Another way can be hot glue

Exactly like a plastic packing machine! But I guess for that I need some space and pressure from both sides. This is not available here with my product.

Make two parts and thread are not viable solutions. They may be able to do what I need at the moment but price difference is much higher! I need a price efficient technique.

Also put even much more material on another is not necessary, because I have at least one product on my hand and attached it for you that achieve a good weld with at most 5 mm of material on another.

As for what @dvmdsc and @lyn said, I guess that is possible to use a technic like all other bag sealing machines. But still it is not as simple as put two parts together and apply pressure. And what is hot glue? Can anyone give me some idea about where to get it and how to use it to get results?

"Hot glue" Hot - melt adhesive - Wikipedia

Is a viable option and very inexpensive. But SLOW! And somewhat messy.

A cheap gun and glue sticks can be bought for $10-15.00 USD. Give it a try, but be prepared to be disappointed.

My suggestion:

For a few parts - hot glue

For a small series - make a simple set up with a lint - get a stander to hold the ring in place for reproduction

For bigger series - automate and work with a 2 pieces (halves) heated press

If these proposals looks difficult - get help

good luck

thanks everybody for your suggestions.

Sorry to reply so late, but no one mentioned RF, or dielectric welding. Could be worth a look.

thank you. the problem is precision not that i cant weld with ultrasonic, but a little displacement in every one of bags and caps can cause a lot of waste in production line.

i need something that is not that much susceptible to poor accuracy of hand placement of bags and caps!