Wire harnesses are typically assembled manually. A full-scale 2D drawing of the harness is printed with a plotter and attached to a piece of plywood. Assorted clips and nails are then attached to the board at key locations on the drawing, such as ends and breakouts. Assemblers then manually route the wires from point to the next like a giant game of connect the dots.
When it comes time to assemble a new harness, the process starts all over again with a fresh board. The old board—with all its clips, nails and fixtures in place—gets put away until it’s needed again. A high-mix shop might keep dozens or even hundreds of such boards on hand. That’s no small expense. What’s more, storing all those boards can be a nuisance. They take up a lot of space, and moving them on and off the shop floor represents an ergonomic hazard.
Engineers at Panduit thought there had to be a better way. They set out to design a reusable harness layout board that could be reconfigured quickly and easily. The end result is the Quick-Build harness board system, which was introduced last month. According to Robert J. Krisel, vice president of the OEM business unit at Panduit, this modular, flexible system promises to:
reduce the cost of creating a wire harness layout board by 65 percent.
reduce the cost of wire harness assembly by 18 percent.
reduce the amount of storage space needed for layout boards by 50 percent.
“Looking at the marketplace, we are seeing more local sourcing of wire harness assemblies and a lot more high-mix, low-volume operations,” says Krisel. “The Quick-Build system was really designed for that environment.”
Tiles and Pegs
The base of the system is a 1 foot by 1 foot plastic grid tile with 20 rows of 20 holes. (Tiles are supplied in packs of eight.) The tiles can be fixed to a plywood board with screws. Alternatively, they can be attached to each other with special connectors so the entire grid can be moved more easily. Notches and ridges on the sides of each tile ensure correct alignment.
As with the traditional nail-board method, a full-scale drawing of the harness can be fixed atop the grid of tiles. Unlike a nail-board, there is space beneath the tiles to facilitate routing of wires from test instruments.
The holes in each tile accept repositionable mounting pegs. Once the peg is inserted into a hole, a quarter turn locks it in place. A rubber washer at the base of the peg provides clamping force to keep the peg in place. It also prevents tears to the drawing.
“The pegs have a locking mechanism that’s more effective and durable than nails or magnets,” says Krisel.
By themselves, the pegs don’t hold wires. Rather, they’re designed to accept various wire-holding accessories, including single-nail wire holders, five-nail wire holders and mounting platforms. Detents molded into the base of each accessory allow it to be rotated within the peg for easier routing of branches and breakouts.
Accessories are molded in black, gray or white plastic so engineers can use color-coding to assist technicians during assembly.
The mounting platforms come in two sizes: 1.2 by 1.2 inches and 1.75 by 1.75 inches. The platforms accept standard, screw-attached harness assembly accessories, such as elastic retainers, bundle retainers, corner posts, wire-end holders, fanning strips, wire breakout springs, standoff posts and test fixtures.
Accessories stay in place until it’s time to assemble a new harness. At that point, they can be removed and reused. The drawing can be stored (in much less space than a plywood board) or reprinted. If the harness needs to be produced again, the pegs and accessories can be quickly reattached in exactly the same positions as before.
“The ability to reuse accessories—especially text fixtures—can save harness shops a lot of money,” says Krisel.
The accessories raise the harness assembly at least an inch above the board. Elevating the harness makes it easier to install cable ties, labels and abrasion protection products. The elevated position is particularly handy if cable ties are installed with an automatic tool.
“If you’re using the traditional nail-board approach, the harness tends to lay flat on the board,” explains Krisel. “Trial users of the system were able to reduce harness assembly time by 18 percent just due to the fact that assemblers aren’t constantly lifting the harness off the board.”
Developing the Quick-Build system took some doing. Panduit engineers spent time at harness shops, learning their problems and observing the assembly process. Trial users provided valuable insights on product offerings and design. For example, the tile-to-tile connector was developed in response to user feedback.
“We assumed that our customers would always want to screw the tiles to a board, but quite a few wanted the ability to just lay the grid on a table,” says Krisel.