As you can probably imagine, we are asked this question a lot. Further, as you can imagine, there are lots of answers based upon who we are dealing with. Is the question coming from a large manufacturer of protein powder who is packaging using a stand up pouch or are we dealing with a small start up packaging dog treats in a stock stand up bag? We deal with companies of all sizes so the best way is to try to answer these questions so everyone is covered. If some of this is old hat, fine, but to some of you the answers will be just what you were looking for.
Stand up pouches, either custom printed or plain stock bags, are made from multiple layers of barrier film laminated together. These layers provide the barrier properties to keep the contents fresher for longer as well as the strength so the pouch can stand effectively and be strong enough to avoid puncture and such. So, with this in mind, we are not dealing with Hefty trash bags or even the cheapo produce bags at the store. We have at least 4.5 to 5 mil thick film that needs to be sealed. Further, what you are sealing is in reality only the innermost layer of the pouch itself. This inner layer is made generally from polyethylene, as it heats and melts pretty easily. However, see the picture at the left. In order to seal the pouch, the open end needs to be placed in between these "clamps" or jaws. The clamps are hot when the clamps are closed together the plastic melts. NOTE...there is a fine line between not enough heat and too much heat, but the concept is what I want you to understand. The thicker the film, the longer it will take to seal and/or the higher the temperature needs to be on the clamps. Make sense?
Further, there are much more sophisticated heat sealers, fast, automated, etc...but when we are asked how a stand up pouch is sealed we do two things. One, we describe the clamps/jaws like I did in the paragraph above. Then we refer them to Sealer Sales in California. These people rock...we do not make a dime from endorsing them...the have any number of available heat sealers and we recommend them highly.
Now, as far as filling stand up pouches, this is only done through the open end or top of the pouch. Remember, a stand up pouch is made from sealing layers of film together and the bottom is completely sealed in such a way as to create the bottom gusset so it will stand. We have large multi-national firms that have automated equipment like the picture on the right. The pouches are running and they get to the "cones" or augers on the left and a certain amount is discharged into the pouch.
We have other customers who use only an auger dispenser like on the left. Here their product is loaded into the auger and they manually hold the stand up pouch and a certain amount is dispensed.
Finally, we have customer who literally fill their pouches by hand...they open the pouch, place or scoop their product in, weigh it and seal it.
So, like I mentioned originally, we have all types of clients so we have all types of answers when it comes to filling and sealing stand up pouches.
Regardless, having someone you can trust, a supplier you can count on to fill your product is always a good option too. A good contract packager is hard to find but well worth the money.