Repair Paste for Polyethylene Rotational Moulded items
from Lysis Technologies
The problem
Lysis Technologies was approached by one of its customers to assist them as they encountered occasionally minor defects/faults of poorly rotational moulded items. Since these specific items were components for the automotive industry or for similar industries, it was crucial to have a perfect finish and final good appearance. Otherwise, the item was not meeting customers specification and expectation and was considered as a reject. In addition, rejected products were leading to lost manufacturing time and wasted energy as well as intangible costs, such as loss of customer credibility.
Specifically, incomplete or deformed edges needed to be reconstructed or large air blowholes needed to be patched up.
In most cases these problems cannot be predicted before the product is manufactured and cannot therefore be avoided through mould design, process parameters etc.
Common reasons are the continuous wear and tear of mould-coatings, poor mould venting or low heat transfer where the PE powder is obstructed from flowing efficiently. Typical defects are illustrated in Figure 1.
Fig. 1: Typical faults observed on poorly rotational moulded items that could be classified as rejects
The Approach
Lysis Technologies carried out a number of visits at customers’ site and assessed the problem, working closely with the shop floor people. The customer’s operational set-up was assessed and potential solutions discussed. The decision taken was to create a bespoke product that fits exactly in customer’s operational design. Initially various prototypes were formulated in the lab and tested. That was followed by trials on site together with operators in order to develop the optimum solution.
The solution
A Repair Paste was designed and formulated by Lysis Technologies in order to be applied directly onto the affected areas using a spatula or just by using a finger to patch up the fault. A subsequent heat-curing process using a soldering iron, heat-gun or flame torch is necessary to achieve a permanent smooth repair.
The consistency of the Repair Paste can be tailored to allow optimum application and finish. For example, an easier breakable paste is required to better fill up the smaller wholes, whereas a paste with a stronger body is preferred when larger areas need to be reconstructed. In addition, the paste is individually colour matched for seamless repair.
Comparative examples can be seen in Figures 2 and 3. Figure 4 includes detailed application steps. Application video links can be found on the web for clarification
https://www.youtube.com/watch?v=UXf9iSk7Zqc
https://www.youtube.com/watch?v=oF6BU2L8yDg
Fig.2: Multiple blow holes on product (left). A black Repair Paste was applied, filling up the holes and cured with a soldering iron (right).
Fig 3: Larger areas were repaired using a colour-matched paste with stronger body and subsequently cured using a heat gun.
Fig.4: A larger area needed to be repaired (see far left). The sequence of images demonstrates a step by step application of a colour-matched Repair Paste. The putty was applied and formed by hand to reconstruct the faulty area. A soldering iron was used to heat-cure and touch-finish the repaired area.
Benefits of the Repair paste:
- Permanent, seamless repair
- Reducing scrap and waste rate
- Colour matched
- Bespoke formulated, characterized by optimum putty consistency for ideal application
- Food Contact Approved
- Easy and swift application
For more information and samples please contact Lysis Technologies on [email protected]
http://www.lysistechnologies.com
