How is life achieved calculated?

Parts made on a life divided by the standard life for that tool. Over several changes the workbook divides the sum of parts made by the sum of standard lives, so it never averages percentages. An edge with a 120-part standard that chipped after 84 parts achieved 84 / 120 = 70 percent.

How is the cost of one tool life worked out for a tool that is reground?

The price of a new tool plus the cost of its planned regrinds, divided by the number of lives. A 72.00 end mill reground twice at 22.00 gives three lives: (72.00 + 2 x 22.00) / 3 = 38.67 per life. For an insert with four edges and no regrinds it is simply the price divided by four.

What does spend above standard mean?

Tool spend is the cost of every life used up. Standard cost is what the parts made would have cost if every life had reached its standard. The difference is the tooling money lost to early changes. A 14.80 insert with four edges costs 3.70 per edge; an edge that makes 60 parts against a 120-part standard has a standard cost of 1.85, so 1.85 of that edge is spend above standard. It leaves out machine time, scrap and set-up, which a broken tool also costs.

Can I compare cost per part across different tools?

Per tool, yes: the By tool block shows each tool's cost per part against its cost at standard life. The workbook does not add cost per part across tools, because a part cut by four tools carries all four costs and the log does not know which tools each part number uses.

Where does the standard life come from?

It is your number: the count the tool-life counter on the control is set to, or the planned parts per edge on the process sheet. The workbook does not use catalogue or published tool lives. After a few weeks of logging, life achieved above 100 percent with no wear failures suggests the standard can be raised.

Can I track more tools or machines than the example?

Yes. The Setup lists and the change log are Excel tables that grow as you type. The dashboard's by-tool, by-machine and Pareto blocks are sized to the example lists; the Method sheet says how to extend them and the dashboard shows a warning when a list is longer than its block.

Maintenance and Reliability

Cutting Tool Life Tracker Excel Template

Log every insert edge and tool change with the parts it made and why it came off, and see which tools fall short of their standard life, why, and what the short lives cost.

Overview

This cutting tool life tracker is a working Excel tool for CNC shop leads, manufacturing engineers and tool crib managers. It ships with six weeks of example tool changes for a fictional job shop with two CNC lathes, two vertical and one horizontal machining centre and eight tracked tools, including a roughing insert that starts chipping when a new job with an interrupted cut arrives, so the dashboard has a story on day one.

Each row is one tool life: an insert edge indexed, a set of milling inserts changed or a solid tool swapped. The workbook looks up the tool's standard life and the cost of one life (price plus regrinds, spread over the lives the tool gives), then calculates life achieved as parts made over standard life, tool cost per part, and the standard cost of the parts made. A change reason grouped as Planned, Wear, Premature failure or Other tells worn-out tools from broken ones.

The dashboard forms every figure from sums, so a short life and a long life weigh by the parts they made. Spend above standard is tool spend minus the standard cost of the parts made: the money that early changes cost in tooling alone. For one insert at its standard life the cost per part is the same as the Insert Cost per Part calculator on this site.

What this template includes

Tool change log with dropdowns for machine, tool and change reason, and data validation on every input
Tools list on Setup with price, edges or regrind lives, regrind cost and standard life, and the calculated cost per life and standard cost per part
Per change: life achieved against standard, tool cost per part, the standard cost of the parts made and a life status in words against your target
A Check column that names data errors: tools, reasons or machines missing from Setup, counts far above the standard and planned changes well short of it
Change reasons grouped as Planned, Wear, Premature failure or Other, so worn-out tools are separated from chipped, broken or crashed ones
Dashboard with machine and date filters, life achieved, premature failure share, tool spend and spend above standard, filtered tiles for changes and the weakest tool
Charts of life achieved by tool, a Pareto of early changes by reason, cost per part actual against standard, and weekly spend at and above standard
Roll-ups by tool, by machine and by week, a Method sheet with every formula, a Verify sheet that re-checks them against an independent reference, and a CSV with live formulas of the change log

Suggested use case

Use it to find the tools that break or wear out before their standard life, to show what that costs, to test a new grade or cutting data against the old one, or to set tool-life counters from real counts instead of guesses.

How to use it

On Setup, type your shop name, currency label, life achieved target and premature failure limit.
Replace the example machines, the tools you want to track (price, edges or regrind lives, regrind cost, standard life) and the change reasons with their categories.
On Tool Change Log, add one row each time an edge is indexed or a tool is changed: date, machine, tool, part number, parts made on that life and the reason.
Fix anything the Check column reports.
Open the Dashboard, set the machine and date filters, and start with the tools at the top of the early-change Pareto and the lowest life achieved.

Frequently Asked Questions

How is life achieved calculated?: Parts made on a life divided by the standard life for that tool. Over several changes the workbook divides the sum of parts made by the sum of standard lives, so it never averages percentages. An edge with a 120-part standard that chipped after 84 parts achieved 84 / 120 = 70 percent.
How is the cost of one tool life worked out for a tool that is reground?: The price of a new tool plus the cost of its planned regrinds, divided by the number of lives. A 72.00 end mill reground twice at 22.00 gives three lives: (72.00 + 2 x 22.00) / 3 = 38.67 per life. For an insert with four edges and no regrinds it is simply the price divided by four.
What does spend above standard mean?: Tool spend is the cost of every life used up. Standard cost is what the parts made would have cost if every life had reached its standard. The difference is the tooling money lost to early changes. A 14.80 insert with four edges costs 3.70 per edge; an edge that makes 60 parts against a 120-part standard has a standard cost of 1.85, so 1.85 of that edge is spend above standard. It leaves out machine time, scrap and set-up, which a broken tool also costs.
Can I compare cost per part across different tools?: Per tool, yes: the By tool block shows each tool's cost per part against its cost at standard life. The workbook does not add cost per part across tools, because a part cut by four tools carries all four costs and the log does not know which tools each part number uses.
Where does the standard life come from?: It is your number: the count the tool-life counter on the control is set to, or the planned parts per edge on the process sheet. The workbook does not use catalogue or published tool lives. After a few weeks of logging, life achieved above 100 percent with no wear failures suggests the standard can be raised.
Can I track more tools or machines than the example?: Yes. The Setup lists and the change log are Excel tables that grow as you type. The dashboard's by-tool, by-machine and Pareto blocks are sized to the example lists; the Method sheet says how to extend them and the dashboard shows a warning when a list is longer than its block.