The way a camshaft is machined has a profound effect on engine performance, timing accuracy and how long components last. Using the right machining methods keeps manufacturing costs low and gives outstanding surface finishes along with tight tolerances. In this blogpost we will explain all machining steps, quality standards, the necessary tools and expert tips for producing camshafts at the highest level.
What is Camshaft Machining
Basically camshaft machining means removing material from raw camshaft blank and shaping it into exact cam profiles. In this process, special CNC tools are used which cut the lobes and journals to the required shapes. Here precision matters a lot because the camshaft’s profiles set engine valve timing and influence how the engine performs.
Also See: A Complete Guide to Camshafts
The Fundamentals of Machining
During camshaft machining, special attention is required regarding materials, precision and geometry. The process begins by selecting a suitable alloy. For standard engines, cast iron is mostly used whereas billet steel is chosen for high performance applications. Each lobe on the camshaft has a complex shape. Therefore advanced CNC machines are needed to form these contours accurately.
It is also important to maintain a smooth surface and tight tolerances because even small imperfections can reduce durability or disrupt engine timing. To keep the camshaft rigid and minimize mistakes, machinists use custom fixtures and steady rests during the process.
A Step by Step Camshaft Machining Process
1. Rough Drilling and Turning
In the first step, both ends of the camshaft block are center drilled. These drilled points later serve as a reference for mounting the block between lathe centers.
Operators then remove the clearance material from the shaft diameter through rough turning. This step sets the basic dimensions before detailed machining begins. Generally six journals are turned using neutral, rough, left, and right cutting tools. This initial phase is completed with grooving and parting.
Also See: Difference between CNC Milling & Turning
2. Rough Profiling
Rough profiling shapes each camshaft section after the initial turning is finished. Operators form the basic contours of cam lobes, bearing journals and the drive snout.
Heavy duty cutting tools are used which remove material quickly but keep the structure strong. At this stage, a 4.5 mm dowel hole is drilled which act as a reference for later steps. This process gets the camshaft ready for precise machining.
3. Precision CNC Milling and Grinding
After rough profiling, precision CNC milling and grinding further refine the camshaft. CNC machines cut and grind each journal and lobe to tight tolerances, often within 0.01 mm, using advanced programming.
High speed grinding wheels which can reach speeds up to 120 m/s are then used to create accurate contours and smooth surfaces. This step makes sure that the camshaft meets strict requirements for durability and performance.
See Also: What is Precision Grinding
4. Heat Treatment
Machined camshafts are then subjected to carburizing to harden the cam lobe surfaces. The parts are heated in furnaces in the presence of carbon dioxide. During heating, carbon atoms enter the steel’s crystal structure.
At this stage, the surface hardness reaches at least HRC 62, with a minimum case depth of 0.120 inches. This treatment is selectively applied to cam lobes with remaining areas protected. This selective hardening keeps the shaft core from becoming brittle.
5. Finish Grinding and Polishing
Finish grinding is the last step of machining. In this step, each lobe and journal is shaped to their exact geometry and size. CNC grinders with CBN wheels are used which achieve tolerances as close as 0.01 mm.
Polishing is done after grinding to remove any remaining surface flaws. Centrifugal barrel finishing is an advanced method used here. It evenly polishes the camshaft using up to two tons of force in only 15 minutes. This process creates a mirror like finish and improves surface quality.
Machining Tools and Equipment
CNC Mills
Modern camshaft production is highly dependent on CNC mills. Both vertical and horizontal types can handle a range of camshaft shapes. In these machines special cutters are used that move along multiple axes to form cam lobes and bearing journals. Newer CNC mills have a spindle power of 37 kW and can handle workpieces up to 1,250 mm long.
Grinding Centers
Grinding centers are designed to finish journals and cam lobes with high precision. In these machines, CBN wheels are used that can reach speeds of up to 120 m/s. Some advanced models also include automated gauging and hydrostatic guideways. In both small run and long run production, these features guarantee consistent quality.
5-Axis Machines
5-axis machining centers have changed the way camshafts are made. They move the cutting tool in five directions. The X, Y, and Z axes provide linear movement while two rotary axes add flexibility. For large camshafts, their head to head designs work best. Whereas table to table setups is best suited for precise work on smaller parts.
Specialized Cutters
Manufacturers use camshaft milling cutters in both solid and indexable forms, depending on the application.
For high precision finishing operations on repeated profiles, solid cutters are used as they deliver maximum rigidity. Whereas for cost effective production, indexable cutters offer versatility because they have replaceable inserts.
The diameter of these tools typically measure between 300 and 500 mm, thus making it possible to machine several cam lobes at once.
Inserts
Camshaft milling cutters use inserts as their replaceable cutting edges. Commonly these inserts are made from material like cubic boron nitride (CBN) and solid carbide. They offer high hardness and resistance to wear. Some designs provide up to eight cutting edges per insert. This reduces tooling expenses and increases productivity.
Toolpath CAM
Toolpath CAM software is used to create the exact toolpaths needed for machining complex camshaft shapes. Advanced systems such as CAM TOOL or Autodesk Fusion automate the generation of toolpaths. Moreover they optimize cutting strategies and allow users to simulate machining before starting production.
Companies like Richconn use AI powered CAM workflows. This approach cuts programming time by 40% and still achieves accuracy of ±0.002 mm.
Achieving Surface Quality and Precision
In camshaft machining, surface quality and precision depend on holding tight tolerances, often just a few micrometers. This is especially true for features like lobes and journals.
CNC grinding and finishing methods such as Micro Surface Enhancement perform an important part in lowering waviness and roughness. These processes can increase the bearing area by up to 70% and help reduce wear. Applying effective cooling, choosing the right tools and maintaining strict quality control lead to smooth surfaces.
Richconn uses exclusive finishing protocols to reach Ra 0.2 μm surfaces which can increase camshaft lifespan by 30% in high RPM engines.
Design Impacts on Machining
The camshaft design has a profound effect on both production expenses and machining speed. For complex lobe profiles, advanced CNC programming is needed which lengthen cycle times. Longer shafts can bend during machining so extra support is needed.
Similarly when a design needs tight tolerances, toolpath planning grows more complicated and production times increase. Optimizing designs helps cut tool wear and makes manufacturing more efficient.
When working with complicated profiles, partnering with a manufacturer experienced in CAM optimization such as RICHCONN can lower cycle times by up to 25% and still keep tolerances within microns.
To Sum Up
In short, the manufacturing of camshafts needs careful material choices, advanced engineering and precise steps at every stage. Each process, from rough turning to final polishing, needs skill and accuracy.
If you need CNC machining services for manufacturing camshafts then Richconn is your best option. You can contact us any time.
Related Questions
1. Which materials should you choose for cost savings or high performance?
For standard or budget friendly camshafts, chilled cast iron is the best choice. If you need maximum wear resistance and strength for performance engines then billet or forged steel works best.
2. What is the usual time needed to machine a camshaft?
Generally it takes 35 to 75 minutes to machine a camshaft. However exact time depends on complexity of design and production method used.
3. Are CNC machines always superior to manual grinding for camshafts?
CNC grinding provides better repeatability, accuracy and speed, particularly for large batches or complex shapes. However for low volume or custom work, manual grinding is more suitable.
4. What is the purpose of degreeing a camshaft?
Degreeing a camshaft sets the valve timing exactly right. This process helps the engine reach the manufacturer’s targets for efficiency and power.
5. Why is software simulation important for camshaft machining accuracy?
Software simulation allows you to perform virtual checks before real machining starts. It helps keep the process precise, finds toolpath mistakes and avoids collisions.
6. In what ways does machining differ for OHV and DOHC camshafts?
OHV camshafts are shorter and less complicated so they are easier to machine. In contrast DOHC camshafts need more advanced CNC work, complex profiles and tighter tolerances
7. How can machining reduce camshaft runout and what causes it?
Material defects, improper clamping or mistakes during machining can cause runout. Using precise fixturing, strict quality checks and careful setups during machining keeps the camshaft straight and minimizes runout.
