Bonding with adhesives reduces assembly costs
We are always looking for the big win / win, which is when you reduce manufacturing costs and at the same time improve product performance. Often choosing adhesive bonding over mechanical fastening provides the win / win scenario.
REDUCE LABOR COSTS
Welding, brasing, and soldering all require professional training and skill, but we all learned how to use glue in kindergarten! (Yes I said glue again – if you’ve been following my blogs you’ll know the word glue all but gives me a rash. I am happy to report, the therapy is going well and I can now say glue without twitching!) Seriously though, industrial adhesives or engineering adhesives are a bit more than the glue we used in pre-school. Still, it doesn’t require a PhD in engineering to use even the most high tech engineering adhesives.
And although we always recommend following good personal protection practices during adhesive bonding, adhesion seems a fair shade safer than welding as there is no molten metal involved. In addition to the time saved by not having to get garbed up like an astronaut to weld, adhesive bonding is generally a faster process.
Another way that adhesives reduce labour costs is that they are easily automated. Adhesive dispensing and curing stations can be automated to ensure precise application of one and two component adhesive systems. Although many adhesives cure independently with moisture or by mixing, those systems that require heat or light to cure can also be easily automated. Automation not only increases the speed at which production lines can run, it also increases the consistency of the application and cure process. Consistent manufacturing processes can increase quality and reduce rework or scrap.
- Reduce high labour costs associated with skilled professional welders.
- Reduce costs associated with plant safety due to the elimination of potentially dangerous welding equipment and flammable gases.
- Reduce time. Time is money and bonding take less time than welding.
- Reduce manufacturing costs with automation
REDUCE MATERIAL COSTS
To weld or mechanically fasten, thicker grades of metals are generally needed. Since bonding (aka gluing) distributes stress across a larger area, thinner materials can be used.
Glass is another example; when mechanically attaching glass to metal (hinges etc.) thick glass must be used because holes are drilled into the glass for the fasteners. Then upon attaching the fasteners, all of the stress associated to that fastener or hinge is localized to that one spot. When stress is distributed across the entire bond area and when holes aren’t drilled into perfectly good glass, thinner glass can be used.
Machine tolerances of materials can be relaxed. For example, press fit shafts require very tight machine tolerances to ensure parts don’t separate, adding a retaining compound can reduce costs associated with tight machine tolerances as the compound fills spaces between the metal unitising the assembly.
When welding, (metal welding, solvent welding, or sonic welding) similar materials perform best. With adhesive bonding, dissimilar materials can be used. So if metal is required for only a portion of a design, perhaps a less expensive metal, a composite, or plastic can be used throughout the remainder of the design. For one customer who was using solvent welding on a cap and cup type design, the cap needed to be a quality grade of a unique plastic blend. The cup did not, but they were using the same plastic because the solvent was overly aggressive on alternative plastics. Allowing the manufacturer to use the plastics of choice saved the customer 30% on the product costs. The adhesive selected was gap filling providing additional savings in moulding as the tolerances could be greater, but the primary savings was in switching plastics. For others the tight design tolerances are the largest concern.
- Reduce material thickness
- Increase machine tolerances
- Design freedom to increase material options
There are buckets written on weight reduction in the transportation industry (some of it in the previous paragraph). Adhesion distributes stress and can allow manufacturers to reduce material thickness while increasing integrity. Less material – less weight – but it is more than that. Heavy materials are only required where needed and lighter materials (carbon fiber, other composites, and plastics) can be bonded to them. Often only a small portion of the design requires a metal substrate, bonding opens up the choices for the remainder of the design.
Although not as great of a weight reduction as material selection, adhesives weighs less than the mechanical fasteners needed to provide the same bond strength. Although weight reduction (and the associated cost savings) was the primary goal of one manufacturer, the ability to eliminate a costly and intricate inventory of dozens of various fastener types and sizes with one adhesive was a huge value. Previous patterns did not always accurately predict future order patterns and maintaining an appropriate stock of the various fasteners needed was problematic – resulting in rush shipments and overtime to meet customer demand.
- Reduce thickness
- Use lighter substrates
- Eliminate heavy fasteners
REDUCE ASSEMBLY PROCESS ORDER LIMITATIONS & ELIMINATE POST ASSEMBLY PROCESSES
The order of manufacturing processes can be dictated by welding. If parts require exposure to the high temperature needed to weld metal, one certainly can’t have sensitive substrates or electronics already on board. Using room temperature curing adhesives allows the manufacturing engineer the freedom to assemble in-line, in the most efficient order. After assembly with adhesives there is no need for buffing or sealing welds.
For one manufacturer, the metal welding was only done at one of their facilities. They received a delivery of those components weekly. By the end of the week one facility was nearly overrun with work in progress and the other was getting frighteningly low.
Permabond is trusted to perform manufacturing audits at some of the largest manufacturers worldwide. We may be called in to reduce weight, and find savings in reducing fastener costs or be called in to reduce process costs, and find savings in materials.
Note that Permabond does manufacturing audits on all types of processes, including adhesive processes. I recall one time I was called in to help a customer increase line speed. This customer had been using one of our heat cure epoxy adhesives since the dawn of time; switching to a UV cure adhesive allowed them to reduce their utility bill, increase the line speed, use 1/4 the amount of floor space, and eliminate substantial reject rate.
Every manufacturing process has its own unique challenges. By partnering with our customers we are able to understand their needs and challenges and share the latest in adhesive bonding technology to find the best fit for each.
Interested in a process audit? Contact Antala