All About Precision Machining
What Is Precision Machining?
Machining refer to one type of the subtractive manufacturing processes used to shape parts and products. Precision machining operations employ the use of advanced automation technologies—such as CAD software and CNC controls—to achieve higher precision and accuracy in the finished pieces.
The precision machining process begins with a computer design file for the desired part. The file then undergoes conversion into machine instructions, which the machining equipment uses to guide the movement and positioning of the fixture and worktable to carefully remove excess material from the workpiece. Depending on the part and production requirements, industry professionals employ different operations (e.g., drilling, grinding, milling, and turning) and materials (e.g., aluminum, bronze, copper, steel/steel alloys, and titanium).
How Does Precision Machining Work?
Precision machining operations generally occur in three distinct stages:
Pre-Heat Treatment Machining
Pre-heat treatment precision machining operations—also referred to as soft machining operations—occur before the workpiece is subjected to heat treatments, which may alter the surface or workability of the material. Typical operations include:
- CNC turning: uses single-point cutters to remove excess material from rotating workpieces
- CNC milling: uses rotating multi-point cutters to remove excess material from—usually—stationary workpieces
- Drilling: uses multi-point drill bits to cut holes into the workpiece
- Gear hobbing: uses specialized tooling to hob—i.e., cut—splines or teeth into gear blanks
After the initial machining operations, workpieces may undergo heat treatments to add or enhance specific material properties, such as hardness, strength, ductility, elasticity, and workability. Generally, these operations prepare the workpiece for the hard machining stage. Some of the most common heat treatments employed include:
- Carburizing or carbonitriding: used to treat the surface of steel to make it stronger, harder, and more wear-resistant
- Freezing: used to expose steel with retained austenite content to very low temperatures of -120° F to -300° F to turn it into untempered martensite
- Quenching: used to rapidly heat and cool metal to increase its material hardness
- Tempering: used to reduce the brittleness of metals, such as 1045 and A36 mild steels and 4140 and 4240 alloy steels, to enhance their mechanical performance
Post-Heat Treatment Machining
Post-heat treatment machining operations—also sometimes called hard machining operations—occur after soft machining and heat treatment operations. The workpiece at this point is generally much harder, necessitating the use of specialized equipment to penetrate the workpiece surface, such as diamond-tipped tooling. Examples of these operations include:
- Hard turning: used to facilitate or replace grinding operations
- Grinding: used to create smoother part surfaces with tighter tolerances
- Gear grinding: used to facilitate or replace gear cutting operations
- Honing: used to produce interior bores or finish pre-drilled holes
In addition to the above operations, more complex or intricate part designs may require additional processing to achieve the desired part or product. These optional processes include:
- Deburring: used to ensure the finished parts demonstrate the correct dimensional tolerances
- Inspection and measurement: used to ensure the finished parts demonstrate the correct dimensional tolerances
- Assembly: used to assemble individual machined parts into a complete unit
Advantages of Precision Machining
Compared to traditional manufacturing methods, precision machining offers several advantages, such as:
- Higher precision and accuracy. The use of advanced machining equipment in precision machining operations enables industry professionals to produce more complex and intricate designs to tighter tolerances. Additionally, it minimizes the risk of human error during production, resulting in better quality and consistency throughout a run and from one batch to the next.
- Lower material waste levels. As precision machining equipment is less likely to produce flawed or unusable pieces, the amount of material wasted during production is much lower than that of manual machining and other manufacturing equipment.
- Faster processing speeds. The equipment used in precision machining operations can run continuously with minimal operator involvement. This quality enables production orders to be complete much faster without sacrificing quality.
These advantages, among others, ultimately result in lower production costs for manufacturers and better satisfaction in customers.
Precision Machining Services at Impro Aerospace
Impro’s unique capabilities are developed to meet the most demanding application requirements in the aerospace, medical, and energy industries. We produce high-precision and complex machining parts for customers using input materials such as bar stock, plates, billets, and forgings of super alloys, stainless steel, alloy steel, and aluminum. Whether machining aircraft braking system components, aircraft engine components, or hydraulic parts, we have met micro-grade tolerances and delighted our customers with consistent quality and reliable delivery at the product development and serial production stages.
We have invested in special equipment, 4-Axis and 5-Axis machining centers, sophisticated laboratory instruments, and NDT testing facilities, all of which allow us to easily process trial runs, customized short runs, or high-volume production runs. We take pride in our wide capabilities to offer one-stop-shop solutions.
For additional information about our precision machining capabilities or other manufacturing services, contact us today.