Suspension Arm Welding Jig

On the Baja SAE team, as the season shifts into the build phase, and as we finalize the geometry for our suspension components, we need a reliable jig system that can hold 'A-arm' tubes while they are being welded.

The task was to modify the older version of the jig to a lighter, more adaptable version that will be compatible with our current control arms. In addition, the references in the Solidworks assembly need to be set up parametrically so that any modifications to suspension geometry will be automatically reflected in the jig.

Upper Control Arm in Welding Jig

This particular jig is for the upper control arms, and it is compatible with both the left and right assembly without any additional parts. It can simply be flipped over with the blocks installed on the opposite side.

Left Upper Control Arm in Reference to Front of Frame

The jig plate itself is water-jet cut out of 1/4" thick aluminum stock, and the support blocks are machined by the team. Some notable changes from the components used in the 2022 configuration are that several of these blocks have been CNC machined this year instead of made by hand on the Bridgeport, and the tapped holes have been located in the blocks rather than to build plate, so lighter, cheaper components can be replaced if any threads are compromised.

Machine Drawing for Jig Block

All of the jig components including the block shown above take into consideration critical tolerances and stack-ups, while increasing manufacturing efficiency with looser tolerances where feasible. For example, the center hole that constrains the control arm tubing is defined from the surface at +/- .003", while the outer edges of the stock which don't drive any alignment features are machined at only +/- .01".

The following images are of one of the completed modular jigs, and a control arm that was welded on it.