If you have thermoplastics that are part of your product, you likely need to make sure that they have the appropriate combination methods, meaning that you are able to bond them together at a suitable strength so that they will maintain the structural integrity of your product. Here are some tips for welding thermoplastics in order to make sure that you are able to achieve the combination strength that you desire.
1. For Polypropylene:
If you are trying to weld polypropylene, you will need to be sure that you are at a high enough temperature, preferably around 300 degrees Fahrenheit. The reason for this is that it will allow you to soften the plastic to the point where a bond is able to be formed. Once you at that point, it should be relatively easy to make sure that polypropylene is able to have a strong bond with the other parts of your product. Polypropylene is one of the easier thermoplastics to bond.
2. For Polyethylene:
If you are trying to weld polyethylene, your first step is making sure that you are welding to the correct surface. You can weld a low density polyethylene rod to a high density polyethylene sheet because the sheet will be able to take the power of the bond and the rod will be easy enough to melt down. However, you cannot weld a high density rod to a sheet that is made out of low density polyethylene. It is a lot harder to fully break down a high density plastic of this type and will therefore make it nearly impossible to get the right strength of bond.
3. For Both:
Beyond that, you will need to be sure that you are cleaning both the rod and the sheet that you are intending to weld. If there is any dust, dirt, or other types of debris, you will have a much more difficult time getting a strong weld because these will undermine the connection between the rod and the sheet.
You will also want to strongly consider making sure that the sheet has the appropriate surface for a weld to adhere. Make sure that you are sanding or grooving the surface to a point where the weld will be able to have a decent amount of surface area to fully connect with the sheet.
For more information, talk to a company that specializes in plastic welding, such as MGM Plastics.