Top 4 Ways Bonding Reduces Assembly Cost

Rebecca Wilmot
Adhesive Selection and Use, Tips
October 6, 2016

As manufacturers, 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.




Welding, brazing, 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 Ph.D. 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. Simple because 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 faster.

Another way that adhesives reduce labor 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 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.


  1. Reduce high labor costs associated with skilled professional welders.
  2. Reduce costs associated with plant safety due to the elimination of potentially dangerous welding equipment and flammable gases.
  3. Reduce time. Time is money and bonding take less time than welding.
  4. Reduce manufacturing costs with automation


Welding or mechanically fastening generally need thicker grades of metals. Since bonding (aka gluing) distributes stress across a larger area, thinner materials are acceptable.

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. Since the compound fills spaces between the metal unitizing the assembly.

When welding (metal welding, solvent welding, or sonic welding), similar materials perform best. You can bond dissimilar materials. So if you require metal for only a portion of a design, perhaps a less expensive metal, a composite, or plastic can replace it 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 molding as the tolerances could be greater, but the primary savings was in switching plastics.  For others, the tight design tolerances are the largest concern.


  1. Reduce material thickness
  2. Increase machine tolerances
  3. Design freedom to increase material options


There are buckets about 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.  You can use heavy materials (ie metals) as necessary and bond lighter materials (carbon fiber, other composites, and plastics) 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 weigh less than the mechanical fasteners needed to provide the same joint 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. Maintaining an appropriate stock of the fasteners needed was problematic, resulting in rush shipments and overtime to meet customer demand.


  1. Reduce thickness
  2. Use lighter substrates
  3. Eliminate heavy fasteners


Often, welding dictates the order of manufacturing processes. 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, only one facility did metal welding. They received a delivery of those components weekly.  By the end of the week, one facility was nearly overrun with work in progress. The other was getting frighteningly low.

Some of the largest manufacturers in the world trust Permabond manufacturing audits. Requests to reduce weight, find savings in reducing fastener costs, or reduce process costs, and find savings in materials are common.

Note that Permabond does manufacturing audits on all types of processes, including adhesive processes. I recall a request to visit a customer to increase line speed once.  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 a 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 Permabond.

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