In-house CNC tool grinding is becoming increasingly attractive to manufacturers who use a sizable volume of tooling. Driven by environmental responsibility and the need to reduce overall tooling cost, reconditioning generally costs less than replacement and resharpening typically costs less than half of producing a new tool. Endmills can be reground at least three times, making the numbers even more compelling.
Tool service providers typically offer a high-quality, high-precision, resharpened tool aimed to perform nearly as well as original manufacturers’ specifications. But when is it more attractive to in-source tool resharpening?
In addition to lowering costs, a large tool consumer could gain flexibility and reduce turnaround time by bringing reconditioning in-house. It’s not just about tool cost but also the cost of production downtime if the right tool isn’t available when needed. Also, machine shops can run into overly long regrinding times, especially when using unusual geometries. And, a machine shop can carry less inventory as back up if handling reconditioning in-house.
Today’s CNC tool grinders are easier to use, but tools are more complex. ANCA technology automates mixed batch regrinding so the process is easy and effective, but, a company new to tool grinding must consider expenses. In addition to investing in a tool and cutter grinder – which can easily be $300,000 – in-house grinding also requires grinding wheels, workholding, coolant, utilities, floor space, the operator, and a CNC tool measuring machine.
In-house regrinding will depend on the utilization of a tool and cutter grinder. To objectively approach the question, first determine the hourly rate of the investment – this includes the cost of depreciation, interest, floor space, energy, maintenance, and consumables. The cost of the operator will come into the equation based on a one-, two-, or three-shift operation and if the machine has the capabilities to run unmanned.
Based on the hourly rate and estimated cycle time per reground tool, a manufacturer will be able to compare the base cost of in-house resharpening opposed to outsourced services.
Once you have a cost comparison, evaluate soft factors:
- Cost of spares to maintain production during tool regrind
- Outsourced resharpening cost per tool × the number of spindles
- Lost production costs with turnaround/waiting times
- Tool quality
- Other processes, edge preparation, coating
- Service, shipping costs
To automatically pre-set the regrinding process, ANCA and Zoller integrated solutions offer reliable, error-free data transfer, which also includes the wear of the tool measured. Regrinding parameters can be allocated to a corresponding pallet location when a tool loader is used. Once the tool is picked up by the loader and presented to the workholding, ANCA Auto Tool Measurement (ATM) digitizes the tool. The cycle measures the most commonly required parameters for most tool types.
A mixed batch of tools can be automatically loaded for regrinding. ANCA Loadermate software can group the tools by tool type, required regrinding operations, and in-feeds based on the wear factor, setting up a mixed batch of tools for unmanned operation.
A variety of automated regrinding solutions for mixed batches are available – collet loading (tool and collet are getting changed together) or collet changing combined with radio-frequency identification (RFID).
With RFID, information is recorded at the programming station and the tool is coupled with the RFID tag.
The machine picks up the tool and RFID tag, scans the RFID, and automatically calls up the grinding program. The RFID is parked while the tool gets loaded and reground.
With the ANCA RFID solution, customers can randomly load tools into a loader pallet, creating an individual program for each tool. The tool position inside the pallet can be swapped with another tool at any time if a tool needs resharpened in a hurry.
Tool and cutter grinders can run regrinding with an operator or unmanned. The duration of unmanned machining is dependent on the type of loader and the pallet capacity.