What is cycle time? The time from when a task, or series of tasks, is initiated until the time it is completed is called cycle time. For example, the cycle time would be the time a shipping label is printed until it is loaded onto the truck and the system is updated. Alternate definitions include the time taken to load, run and unload a workpiece.
You can easily measure the cycle time of a machine by simply timing the time between pressing the button that starts the cycle for a first workpiece and pressing the next button.
The production quantities of an industry dictate that you need to run more workpieces in order to reduce the cycle times.
You can break down every thing that happens in a Computer Numerical Control machining machine into four categories.
1. On-line, productive tasks:
These are the actual operations that occur in a CNC cycle. These include the drilling, tapping and reaming operations that help to complete the workpiece. Two methods can be used to minimize cycle time in these areas. The other would be to plan carefully.
The process engineer will have to select the appropriate machine tool, cutting instruments, fixturing, and order of machining according to the number of workpieces being machined. This will be determined based on the production volume. The process used to machine workpieces will affect the cycle time.
If you have not yet implemented your company’s processes before you start your program to reduce cycle time, the second option would be to optimize cutting operations. This would involve selecting the best cutting tool materials, feeds and speeds in order to machine as many workpieces efficiently as possible within the current process.
2. On-line, non-productive tasks:
These are tasks performed during the machining cycle but do not directly contribute to the completion of the workpiece. Computer Numerical Control specialists often look for ways to improve program execution time. These are the things like rapid movements, tool changes, M-code execution and spindle acceleration/deceleration. It is easy to reduce the time it takes for programs to execute in this area.
It is often enough to monitor the production run for just a few workpieces and find the times when the program can change to eliminate any noticeable pauses. It is important to remember that these workers must not ignore other processes. They might be so focused on program execution that they neglect other operations. This could lead to serious waste of cycle time. Machine Shop In Fremont, CA
3. Off-line, non-productive tasks:
These are the tasks in the machining process that do not aid the completion of the piece. These types of tasks can be done while the machine is producing workpieces. They do not add to the overall cycle time. If there is little to no work during long machine cycles, the operator can be freed to perform productive tasks off-line.
4. Off-line, productive tasks:
These tasks are performed by the CNC machine while it produces workpieces. This is extremely useful during long CNC cycles. Tasks in this category can dramatically reduce the time needed to complete the production runs, which would effectively lower the cycle time.