1. Design optimisation: Cut down on the complexity of processing at the source.
Cost control begins with the design process of car parts. By making geometric shapes simpler, standardising tolerances, and using modular design, you can cut down on tool wear and machining time by a lot. For instance, when optimising a car engine cylinder block, the irregular surface on the inside was changed to a regular one, and the whole structure was split into three separate modules. This made processing 40% more efficient and cut the scrap rate from 15% to less than 5%. The specific design rules are:
Standardising the internal fillet: The fillet radius at the vertical connection of the groove body should be at least one-third of the groove depth, and the size should be standardised to cut down on the number of tool changes. For instance, you can use an 8mm diameter tool to process a groove that is 12mm deep and has a 5mm rounded corner all at once.
Stay away from structures with thin walls: It is best for metal parts to have walls that are at least 0.8 mm thick and plastic parts to have walls that are at least 1.5 mm thick. Processing thin walls is prone to vibration deformation and needs extensive route adjustment, which makes the processing time go up by more than 30%.
Control of thread depth: To keep tools from wearing out too quickly, the thread depth should not be more than three times the diameter of the screw hole. For instance, keeping the depth of the M6 screw hole within 18mm can double the life of the tool.
2. Managing materials: Finding the right balance between performance and cost
Material costs make up 60% to 70% of the entire cost of CNC machining, so it's important to choose materials that are cost-effective based on how the parts will be used:
Alternative material application: For parts that don't have to support weight (like interior brackets), aluminium alloy (which is 40% cheaper than stainless steel) can be used instead of high-strength steel. For plastic parts, POM (which is easier to work with than ABS) or nylon composite materials are better.
Recycling trash: The material utilisation rate has gone up from 75% to over 90% by using CAD layout to make the cutting plan better. For instance, nested arrangement was employed to cut the cost of single piece materials by 18% when making a gearbox housing.
Evaluation of the process: There is a positive relationship between the hardness of materials (HRC) and cutting force. When you use hard alloy cutting tools to work with high-hardness steel (such 42CrMo), the cost of the cutting tools can be as much as 25% of the overall cost. When you use aluminium alloy cutting tools, the cost is only 5%.
3. Technological Innovation: Making processing faster and more accurate
Machining technique at high speeds: Using a high spindle speed (≥ 15000rpm) and a shallow cutting depth (0.5–2mm) can minimise the machining cycle time by more than half. For instance, when making the housing for a new energy vehicle motor, high-speed milling cut the time it took to make one piece from 45 minutes to 22 minutes.
Five-axis linkage machining: By dynamically adjusting the tool axis vector, you may cut down on the number of times you have to clamp. For example, when machining a turbocharger blade, a five-axis machine tool can do all of the surface machining in one clamping. This makes the process three times more efficient and cuts labour costs by 60%.
Tool path optimisation: Use an adaptive cleaning algorithm to spread the load evenly among the tools. One scenario of machining an engine piston demonstrates that after optimisation, the tool life went from 8 hours to 20 hours, and the cost of a single tool went down by 65%.
4. Running and maintaining equipment: cutting expenses over the whole life cycle
System for preventive maintenance: Making plans for frequent maintenance, calibration, and parts replacement can cut the number of equipment failures by 70%. For instance, a machining centre has raised its overall equipment efficiency (OEE) from 65% to 88% by doing daily checks and major repairs every three months.
Energy management: Using a variable frequency spindle and servo drive mechanism to lower power use when the machine is not in use. After a given production line was remodelled, a single machine tool saved 12,000 kWh of energy per year and cut the cost of electricity by 15%.
Strategy for upgrading equipment: buy high-precision five-axis machine machines for items that offer a lot of value, like gearbox gears. A three-axis machine tool can suit the needs of simple structural parts like brackets. By using equipment grading design, one business has enhanced the return on investment of its equipment by 40%.
