Residential gas water heaters have long been considered safe when properly used. Yet the potential dangers resulting from the improper use and storage of gasoline and other flammable materials in the vicinity of the water heater have continued to be a concern among manufacturers of residential gas water heaters.

Molten zinc alloy is not commonly considered as an instant curing “glue,” nor as an alternative to instant-cure adhesives for bonding small components. But it has been used for more than 60 years in FisherTech’s Injected Metal Assembly (IMA) process to join components in much the same way as adhesives. While zinc alloy can’t replace adhesives in all applications, it can do so in many assemblies without the problems of peeling and thermal degradation inherent with conventional adhesives, and without the need for special surface preparation.

There are many critical plastic-part assembly applications where the long-term integrity of the joint is absolutely essential, such as when the assembly must contain a liquid. Examples include various small household appliances, oral hygiene appliances, or parts for major appliances, such as a dishwasher arm or clothes washer pump assembly.

Combining materials of choice is important for the appliance industry where “form follows function” is archetypal. Appearance, performance, cost, and assembly ease constantly dog the engineering community in this industry. This is particularly true when joining dissimilar materials, such as metals and plastics, into one unit or subassembly.

When an application requires two thin metal sheets to be joined permanently face-to-face, designers routinely have turned to rivets, welding, or adhesives and tapes. But tradeoffs loom with each of these methods. An innovative fastener design using clinch technology provides a more practical and less complicated joining method that is able to perform multiple functions and expand design possibilities.

Edge-forming rollers join round assemblies.

Tubing, cylindrical housings, and similar shapes often pose joining challenges. Crimping and pressing operations have been frequently used to form an edge on such shapes as a means of joining them to another part or to enclose an assembly of parts, but those methods have their drawbacks.

Relays switching at minimal loads require clean contacts.

Selecting joining method should precede joint design.

Use of thinner sheet metal makes proper threaded fastener selection more critical.