Do you set your cutting tools offline? If the answer is no, you’re losing money. And you’re not alone.
Offline tool setting is one of those things shop managers and machinists often read about but seldom try. One reason is the intimidation factor. Setting tools offline may require you to re-evaluate how you set up and plan jobs.
If yours is like most shops, you’re always under the gun. When you finish one job, you clear off the chips—maybe—then start reloading tools and reprogramming the CNC. You also probably clamp the part in the vise or fixture, put the tool in the spindle, touch the tool off the top of the workpiece and then touch the edge finder to the workpiece. This method is wasteful. Offline tool setting eliminates some of this waste.
But what about the expense? Few shops can afford all of the extra tooling needed, let alone purchase one of those fancy tool presetters featured in magazines.
Consider for a minute, though, the cost of machine downtime. Let’s assume that a one-person shop charges $70 per hour and averages one hour of setup time for each job. Of this hour, half could easily be spent preparing tooling: clamping cutting tools in holders, inserting holders in the machine and touching off the tools. If one job is set up every day, more than 125 hours a year would be spent setting tools. This adds up to $8,750 in lost machine time annually. A larger shop, one with 10 machines working two shifts, for instance, could easily lose $175,000 in a year.
Moreover, these examples don’t take into account the machine time lost after a job is up and running. Tools break or become dull and need to be changed. A machine that sits idle while the operator scrounges around for a new tool is losing money—often, more money than the value of the tool being replaced. Compared to the cost of an idle machine, the price of a spare tool and toolholder is insignificant.
The aim of a machine shop is to keep its machine spindles turning continuously. That, of course, is impossible to achieve. But any shop, including yours, can boost machine uptime by setting tools offline. Accomplishing this takes a little planning, money and, perhaps most importantly, a basic understanding of coordinate systems and machine programming.
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