Eliminating pre-machining operations is often the difference between winning bids and profitability.
While trimming labor costs is difficult and sometimes personal, it has become a necessity to compete in today’s worldwide economy. Typically, reducing labor costs, which are the largest portion of a shop’s costs, requires an upfront capital investment in new machinery or processes. However, shops can reduce labor costs 20 percent or more without an investment by using machine-ready blanks. They are furnished to net sizes, ready for final machining. This eliminates fly-cutting and squaring up, as well as extra clamp changes, tool changes and fixture offset adjustments. Shops using machine-ready blanks are more efficient and lean, which significantly cuts the overall cost of parts.
The operations eliminated by machine-read blanks usually blend into the program, making it difficult to calculate their full cost. Yet eliminating time-consuming, non-value added pre-machining operations is often the difference between winning bids and profitability. Calculating the true value and cost savings of machine-ready blanks is dependent on identifying all the pre-machining operations.
Gain Machine Time
As a recent example, a machine-ready blank eliminated more than 11 minutes of in-house pre-machining on a rough blank and 15 minutes of operator intervention time, including five clamp changes. Machine-ready blanks cut $5,000 off the complete cost of the job even though they cost slightly more than starting with raw stock. Using machine-ready blanks in this application reduced machine time by 32 percent, or 216 hours in this case, and freed a month of production time that could be used for more parts or jobs.
Material: 3/4 × 9 7/8 × 16 3/8 inches (oversize)
Quantity: 500 pieces
Prep Machining: 11.12 minutes
Operator Intervention: 15 minutes (such as changing clamps)
Finish Machining: 54.83 minutes
Total Run Time: 81 minutes
Material: 0.625 × 9.700 × 16.250 inches
Tolerances: ±0.001-inch Thickness, ±-0.002-inch W/L
Flatness: within 0.002 inch
Quantity: 500 pieces
Prep Machining: 0 minutes
Operator Intervention: 0 minutes (such as changing clamps)
Finish Machining: 54.83 minutes
Total Run Time: 54.83 minutes
Machining cost savings: $40 per part (26 minutes per part)
Material increase: $30 per part
Total cost savings: $10 per part
Total job savings: $5,000
Machine time savings: 216 hours (32 percent of overall machine time)
Short Runs More Profitable
The smaller the production quantity, the more cost effective machine-ready blanks can be. Consider the percentage of time spent setting up for a short run versus a long run. Whether a job has few or many parts to run, the setup time is the same.
As the quantity of parts decreases, the percentage of time spent setting up and qualifying each part grows significantly larger. This limits the time available for production runs.
For example, the extra expense of qualifying a run of 100 parts with dimensions of 0.5 × 8.0 × 12.0 inches, ±0.002 inch all over, would have consumed 20 percent of the time available to run the entire job. If the job had been only five parts the extra expense of setting up and qualifying the parts would have eaten up closer to 35 percent of the available production time. Jobs that consume more than a third of available production time for setup and qualification are unprofitable without machine-ready blanks.
Cost Of Machine-Ready Blanks
Raw stock might allow a shop to shave as much as 10 percent off the cost of materials, but this results in less than 1-percent savings on overall part cost. Machine-ready blanks cut labor costs 20 percent, which are more expensive than material costs, resulting in a 15-percent lower overall part cost. Even with as little as a 10-percent savings in labor, overall part cost would drop by 7.5 percent.
Increasing Available Machine Time
Shops are often faced with the dilemma of preventing competitors from gaining a foothold with good customers. For example, when a customer has a tight schedule and the shop lacks the capacity, buying a machine isn’t economically feasible. Machine-ready blanks can be effectively used to increase machine production time without any additional investment.
A recent example is a turning shop with limited machining capacity. A long-time customer had a milling job with a tight schedule. The shop lacked the capacity to meet the schedule. The job certainly wouldn’t have paid for the cost of a new machine. Subcontracting the job wouldn’t be profitable either, and it could lead to quality control and scheduling issues. Turning the job down, however, might open the door to a competitor.
Using machine-ready blanks, the turning shop increased in-house milling capacity by 7.5 hours (one full shift). The savings were immediate and the shop was able to meet the customer’s tight lead-time.
Machine-ready blanks can cut costs dramatically without an upfront investment. They provide a no-cost way of increasing machine production time without increasing expendable labor costs or capital investment. While machine-ready blanks might cost slightly more than raw stock, the labor costs saved reduces overall part costs by 20 percent or more.blog comments powered by Disqus