The hard chrome plater faces a challenge similar to that of a machinist or grinder when reviewing a manufacturing drawing while planning operations of the process required.

In the process of working a casting or billet of metal into a complicated machined configuration, an efficient machinist will have a number of fixtures or tools which provide the correct positioning of the material so a drawing design can be met. This calls on the machinist's expertise to develop custom tooling which may be used on only one design or job.

Similarly, a plater must review manufacturing drawings prior to pricing or planning. many designs resemble parts which have been processed before, with differences only in the overall length or diameter size. In these cases, the part becomes an "easy bid" because there are existing racks or fixtures which accommodate the part.

Tooling costs and the amount of time it takes to develop the correct tooling are major considerations of the plater. many times a given part design may be bid by two different vendors with a price and delivery difference which is not understandable to the person requesting the bid. In many cases it's because the low bidder has existing tooling.

Often, unfamiliar designs or drawing specifications received call for more than one surface to be hard chrome plated. This dictates that the plater engineer special tooling to hold or rack the part so the application of chrome can be applied uniformly to the correct thickness.

The need for uniform deposits at a controlled thickness requires an even current distribution. This is provided by the tooling. A correct fixture or holding device is essential to provide the needed amount of current transmitted to the part.

The fixture's ability to carry adequate power highly influences the rate of deposition, and the speed at which a part or group of parts can be completed so the next group can be plated. A rack (see diagram 4.1) may have the capacity to hold five parts to be plated. At the end of a plating cycle, occasionally four parts will have the desired thickness while one part requires more time to finish. This is usually caused by a poor contact area from the rack to the part. Also, the final character of the chrome deposit will be influenced by the arrangement of parts on a rack. If the parts are not properly spaced or are plated too close to the adjacent part, a "robbing" action will occur leaving the parts with uneven deposits.

We hope this overview of the tooling required for hard chrome plating will enable you, the customer, a clearer understanding of the thought and mechanical process that goes into bidding and processing a part to be hard chrome plated.