Dismantling perfectly sound objects like refrigerators, washing machines, or industrial pumps does not appear, at first sight, to be a sensible use of time. However, specialist engineers from Henkel working alongside manufacturers of such items, use the occasion to explore how adhesives and similar technologies can be included in both current and upcoming designs - a process called Tear Down Analysis (TDA). Henkel’s Bob Orme takes up the story:
“We examine every component in the assembly and look at the complexity of the manufacturing process. The overall purpose is to discover new production procedures that are not only more cost effective, but which will also create goods of a higher quality.” Once the TDA is completed, a report is generated, tabulating the results and identifying areas where improvements in quality, function and performance can be achieved. “Exercises such as analysis of manufacturing costs, testing and solution validation are also available through our own laboratories. In the end we’re looking for financial savings, increased performance and improved quality.”
It is important that senior management from the manufacturing company is involved in the TDA and provides support. The customer needs to be open with information about the product, the existing assembly methods, costings, and any problems that have occurred. There has to be a serious commitment involving the right team - including decision-makers - in the procedure.
The process
The analysis starts with the two teams meeting to identify and probe manufacturing problems and process bottlenecks related to the specific item. Armed with that information, the actual Tear Down can begin. Parts are dismantled and existing procedures and products noted. Once that has been completed, a brainstorming session is held at which new design, process improvement and cost reduction ideas are discussed.
“We also make it part of our commitment to identify any unrecognised customer needs,’ says Mr Orme. ‘The intention is to utilise our combined expertise to identify new ideas involving design and manufacturing improvements. Included in our thinking might be component reduction, simplifying complexities in manufacture, shorter assembly time, material savings, improved device performance and the potential for automation.”
A full report of the Tear Down activity, including photographs and, where appropriate, video tape footage, is presented to the customer, along with a summary of the Tear Down team’s observations.
Clearly, confidentiality is vital and it is not possible to identify individual manufacturers who have undertaken these analyses. However, early Tear Downs carried out by Henkel involved refrigerator manufacturers whose models already included a number of adhesive technologies.
The machine disassembly was broken down into five component subcategories: cabinet, doors, liner assembly, electrical, and shelf parts. Each component with potential applications was classified as high, medium or low priority. High priority applications involved those that were obviously strong candidates for conversion to adhesive/surface technology treatments. Although initial plant audits had identified several high-priority manufacturing bottlenecks, the Tear Down process actually uncovered more opportunities for production improvement.
Although these manufacturers already relied on a number of different adhesive technologies, there was still potential for new application areas. For example, the analysis showed that cut gaskets were being employed as an electrical shield and a moisture seal between the control box and the top liner of the refrigerator. Rivets and screws were used to attach the shields to the refrigerator’s top liner. Clearly, eliminating the expensive cut gaskets and rivets, while at the same time speeding up the assembly process, would produce valuable savings. A structural adhesive was recommended that would provide the gasket in addition to bonding the aluminium control box to the polystyrene liner. This change saved processing time and reduced parts inventory.
In order to protect finished refrigerators from damage during transit, foam posts had been manually taped to the four finished corners during packaging. This process was labour intensive and costly - requiring several operators to hold the posts in place and complete the taping. Henkel suggested replacing the tape with a semi-automated application of an adhesive that would bond well to the specified foam, yet release easily from stainless steel and polyester painted surfaces. Each post required just two shots of adhesive. Tests revealed that one operator could bond two posts to the refrigerator in twelve seconds - a process that considerably reduced costs.
The Tear Down also revealed an improved method of bonding product identification nameplates - made of a synthetic single layer film - to the polyester-painted refrigerator doors. Double-sided adhesive tapes were not an option as they would be visible through the film substrate. The proposal was to formulate a clear adhesive that would adhere to the film and the polyester paint. Henkel designed the dispense process to apply the product to the label.
In the end, some fourteen cost saving applications were identified in two refrigerator models.
Another Tear Down concerned the manufacture of petrol station forecourt fuel dispensers. For this process, the dispenser was also divided into several key areas - packaging, cladding/framework, vapour recovery, hoses and nozzles, electronics, and hydraulics. In each category, components were dismantled and assessed for potential adhesive applications. As a result, no less than 26 new applications were identified, of which more than 20 had a high feasibility rating, while the remaining applications were designated for immediate action.
“By redesigning a vapour recovery component, the assembly could be retained using engineering adhesives rather than being threadlocked,” recalls Mr Orme. “This enabled four threads and two pipe fittings to be eliminated, thereby reducing time and reducing tolerances.”
In another application, the existing design of the dispenser door demanded 15 minutes for the assembly procedure. This lengthy task involved the use of 24 weld studs and nuts, washers, spacers, gaskets and a silicone sealer. The Tear Down team suggested a simplified design that saw the window being bonded into the frame. This recommendation not only dramatically reduced the number of parts and assembly time, but also removed the potential for edge corrosion.
According to the manufacturer’s team leader, the opportunity to take the product apart with a group of experts was one that it could not afford to miss. The whole process of examining every part and gaining the views of the entire team brought many new ideas to the table - not only suggestions where adhesives could play a part, but also comments on the design in general. The Tear Down proved so productive and valuable an experience that this manufactured vowed to undertake similar exercises themselves on new development projects.
“We are able to present an unblinkered approach to design,” says Bob Orme. “It is, after all, very easy to continue doing things a certain way, simply because they’ve always been done that way. What we do is provide an opportunity for manufacturers to really scrutinise their own product.”