Manufacturing cycle time is a machine’s estimated time to shape raw material into a finished part. This time may include;
- Material Loading
- Running the Machine
- Tool Changeover
- Part Inspection, and
- Unloading the part.
Besides, it may also cover delays between steps and the transportation of materials. Keeping cycle time short means faster production at lower costs. Generally, Smart factories like ProleanTech, employ modern machines, software, and effective shop-floor practices to reduce waste and speed things up to stay competitive.
In this guide, we’ll look at how cycle time is calculated and ways to improve it so you can manufacture high-quality parts faster.
What Is CNC Machining Cycle Time?
As mentioned before, the production cycle time in CNC machining is the time needed to manufacture a part from raw material to completion, excluding the design phase. It includes cutting, tool changes, and any steps in between. Its familiarity helps you plan jobs, avoid delays, and maximize outcomes.
Here’s the manufacturing cycle time calculation formula: Cutting distance/Feed Rate
However, spindle speed, tool path, and part design also influence the cycle time. Each machining method, like CNC milling, turning, and drilling, comprises lead times.
How to Calculate the Cycle Time Manufacturing for Different CNC Operations(+Formulas)
Usually, manufacturing cycle time includes the cutting time, part movement, inspection, and any time the machine waits. Here are two practical approaches.
The Basic Idea
In theory, you can calculate it like this:
Cycle Time = Cutting Time + Movement Time + Inspection Time + Waiting Time
Some of this time adds value (like cutting), while others, like inspection, waiting, or moving parts, are considered non-value-adding in lean manufacturing.
A More Practical Method
In real time, it’s difficult to track every step perfectly. So most shops use a simple formula:
Cycle Time = Total Run Time/Number of Parts Made
This gives you an average time per part and helps quote jobs, plan schedules, and find ways to save time.
Here is how you can calculate the manufacturing cycle time for different CNC operations.
CNC Turning Cycle Time
Turning involves a lathe that spins the workpiece. Here, a cutting tool shapes it along its length. To find the cycle time, you can use this formula:
Turning Cycle Time = Cutting Length ÷ (Feed per Revolution × RPM)
- Cutting length is how far the tool travels (including the start and end moves).
- Feed rate is how far the tool moves per revolution.
- RPM (spindle speed) depends on how fast you want to cut and the size of the part.
CNC Milling Cycle Time
During CNC milling, the tool spins and moves over the part to create products and parts. The cycle time works the same way as turning:
Milling Cycle Time = Cutting Length ÷ Feed Rate
- Cutting length is the total distance the tool moves.
- Feed rate is usually given per tooth on the cutter.
- RPM is based on cutting speed and the tool diameter.
CNC Drilling Cycle Time
Drilling usually makes holes by pushing a spinning drill bit into the material. To calculate how long drilling will take, use the formula below.
Cycle Time = (Number of Holes × Hole Depth) ÷ (Spindle Speed × Feed/Revolution)
- The number of holes
- Hole depth
- Spindle speed
- Feed rate is how fast the drill moves down into the material
How to Estimate Manufacturing Cycle Time?
Estimating cycle time helps you plan production and control expenses. You can use software tools and perform basic calculations to determine how long a job will take.
Use CAM Software for Accurate Estimates
CAM software simulates the machining process and gives estimated cycle times to aid in planning and scheduling. It helps indicate mistakes during early stages and makes production scheduling easier.
Calculate Time Based on Feed Rate
Manufacturing cycle efficiency is estimated by dividing the cutting distance by the feed rate. This gives a basic idea of how long the cutting will take.
Include Tool Changes and Passes
Always add time for changing tools and for multiple cutting passes. These extra steps affect the total cycle time and should not be overlooked.
How Part Complexity Affects CNC Machining Lead Times
When a part is more complex, it will take longer to machine. These parts often have features like holes, grooves, or tight tolerances. So, they need extra time to machine correctly.
For instance, a block with a few holes will be quicker to shape than a part with curved surfaces, multiple drilled holes, and fine details. Each extra feature adds time for setup, tool changes, and careful machining.
In addition, complex parts may need slower cutting speeds and extra finishing steps to meet quality standards. All these factors increase the machining time and can affect your project schedule and cost.
How Can You Reduce CNC Machining Cycle Time
Reducing cycle time in CNC machining helps you make parts quicker and save costs. First, focus on cutting down non-productive time like waiting and moving materials, before adjusting the machining process. Here are some common strategies to eliminate delays in the machining cycle time.
- Cut Down Idle and Waiting Time: All materials and tools should be prepared before the machine starts. Material Requirements Planning helps ensure that the right parts and tools are on time. So, machines don’t sit idle waiting for them.
- Reduce Movement of Material: Movement of raw materials or final parts around the shop often wastes time. Prepare the workplace to make the materials close to the machine and eliminate excessive movements. Automated inspection can save time, particularly for high-volume production, but manual inspection may still be efficient for complex or low-volume parts.
- Perform Detailed Inspections: Inspecting parts after machining or during is valuable, but it can hamper you. This would be faster and accurate when using digital measuring instruments and automated inspection systems.
- Organize Jobs & Apply Predictive Tools: Plan the sequence of jobs to be carried out. Organize the same-size parts into one group to minimize the shifting of tools and materials. Use digital software to forecast the changes in cycle time.
Key Notes!
Effective communication is a significant factor in making CNC machining efficient. Plan work and check it by using advanced devices and innovative software. The employees handling complicated parts should be trained. These improvements help produce parts in less time. It reduces expenses too, and makes the customers satisfied.
