Manufacturing Alternatives

A trade-off analysis of the following four manufacturing processes will be used to optimize the cab frame design: use of mechanical fasteners, welding, use of structural adhesives, and use of molded fiberglass. All of these processes when used properly can meet the initial cab frame design requirements.

The use of mechanical fasteners involves nuts, screws, and washers. Although this process is simple to design, it has many disadvantages such as follows:

	Requires additional holes in material
	Can require thicker material to increase strength which adds weight and cost
	Can introduce noise into the cab through vibration
	Hardware will rust over time making field service difficult and lowering the lifespan of the machine.

The process of welding a cab frame has been used for many years and is a process that many assemblers are familiar with. This process has good flexibility of design combined with good strength qualities; however, some of the disadvantages to welding include the following:

	Distortion of the sheet metal
	Toxic gas given off when welding galvanized steel may require the installation of an expensive ventilation system (galvanized steel is the preferred material for cab design)
	Burning off of the galvanized layer during the welding process promotes rust over time
	Requires a secondary cleaning process after welding
	Requires new tooling fixture for each design
	Welding of dissimilar materials is difficult.

The use of structural acrylic adhesives to bond the cab frame is a relatively new process at Grove. Some of the advantages are that this process has no odor, does not cause distortion of the sheet metal, has increasing bond strength with time, will not affect the galvanized layer of the sheet metal, does not require new tooling for each design, and can be used to easily bond dissimilar materials together. However there are some disadvantages, and they are as follows:

	Requires additional training of personnel
	Requires additional testing to prove design usage
	Bonding must be done in a clean environment.

The molded fiberglass designs are purchased outside of Grove. The strength and mold techniques make design possibilities endless with this process; however, some of the disadvantages are as follows:

	Low volumes have high cost penalties
	Difficult to change initial design; requires additional tooling cost and tooling design time
	Lead time on molded purchased part is frequently very high.