Twin-deck HDPE or PP pallets can be made by hot plate welding separately molded top and bottom sections. The heated platen melts the internal ribs and perimeter mating surfaces, then withdraws so the sections can be pressed together and cooled. This route is for a permanent welded assembly. It is not a joining step for a pallet already molded as one piece, and it does not make HDPE and PP interchangeable within a joint.
Follow a pallet through the station
1. Locate the separate decks
The upper and lower sections go into tooling that locates their mating surfaces opposite one another. The important drawing is not only the outside rectangle. It is the map of the ribs and perimeter surfaces that will become the welded structure.
Review that map with the tooling layout. A rib that is not properly presented to the heating surface cannot be judged by looking at the pallet edge after welding. Show both molded sections, their material grades and the surfaces that the tooling can support. Identify the largest and smallest pallet variants before treating several sizes as one tooling job.
2. Heat the mating surfaces
The platen contacts the joining surfaces on both sections. The aim is to prepare the ribs and perimeter for joining, not to soften the entire deck. Large-area heating needs attention across the working surface. A single temperature reading does not describe contact at every rib.
Check the molded sections as well as the heater. If some mating areas contact differently, increasing the heating time everywhere may overheat areas that were already ready. Deck geometry, support and heating conditions belong in the same trial rather than being adjusted as unrelated problems.
3. Withdraw the platen and close the joint
Once the mating surfaces are ready, the platen retracts and the press brings the sections together. This joins the internal ribs as well as the outer mating surfaces, creating the hollow-box structure. The closing movement must keep the two sections aligned with their intended joining pattern.
A clean outer edge alone is not evidence that the internal ribs joined correctly. Agree how the trial parts will be checked before accepting a production setting. That review should address the assembled pallet, not only the appearance of a weld sample taken from its perimeter.
4. Hold, cool and release
The pallet remains pressed together while the joint cools. Heating and cooling contribute to the cycle, and pallet size and wall thickness affect the result. Reducing a timer is not useful if the assembly can no longer be released in an acceptable condition.
A welded pallet is a load-bearing product, but welding it does not establish its rated load. Set the finished-pallet acceptance requirements separately. Do not infer a load rating from the press capacity or from a weld that looks smooth.
5. Deal with flash and the next operation
Plan where displaced material will go and whether trimming is required. The pallet must leave the welding station and pass through whatever conveying or stacking comes next. SHNEHP offers residue-removal options and robot or gantry integration for unloading and stacking. The selected handling arrangement needs to be part of the project layout.
Use the trial to answer specific questions
| Trial observation | What to review before changing settings |
|---|---|
| The perimeter looks joined but internal joining is uncertain | Rib layout, contact and the agreed inspection of internal joints |
| Different areas show different melting | Deck support, mating-surface contact and heating across the platen |
| Excess material interferes with the next operation | Joint geometry, pressing conditions and the trimming requirement |
| The pallet cannot be released acceptably at the target cycle | Cooling, support and handling, not just the heating timer |
These are review directions, not diagnoses from appearance alone. Keep trial records tied to the actual material and deck version. An HDPE result is not a production setting for a PP pallet. Nor does the fact that both materials are used for pallets establish that an HDPE deck can be welded to a PP base.
Define the pallet before selecting the machine
The SHNEHP pallet welding range includes XNTP-90 and XNTP-91. We build large-format tooling for the top and bottom decks, with pressing for broad joining areas. Equipment specifications are confirmed for the particular pallet and tooling configuration.
For a proposal, provide the two deck drawings, material grades, pallet variants, acceptance requirements and the planned flow into and out of the station. Add the target output and available factory layout. The machine is large and heavy, so floor loading and installation access need review even before a final equipment arrangement is chosen.
We offer free welding samples with your own parts. Use that stage to establish the joining and handling requirements rather than borrowing a cycle time from a different pallet.
Websites: shnehp.com | shnehp.cn
Request a Technical Consultation
Send your part drawing, sample information, plastic material and target cycle time. Our engineers will recommend a practical hot plate welding machine configuration.
Information in this article is taken from: /pallet-welding-machine/, /welding-and-testing-fixture/