How to Choose Cams for Circular Knitting Machine Parts

Cams are essential components of circular knitting machines, playing a critical role in controlling the movement of needles and sinkers. These parts determine the form and precision of the knitting process, directly affecting the quality of the final fabric. Cams can be categorized into different types based on their function, including needle (looping) cams, half-clearing (tucking) cams, flat (floating) cams, and sinker cams. Selecting the right cams is crucial for optimal machine performance and fabric quality. Here’s a comprehensive guide to choosing the best cams for your circular knitting machine.

1. Understand Fabric and Design Requirements

The first step in selecting cams is to consider the type of fabric and its specific requirements. Each fabric design demands a unique cam curve due to differences in style, texture, and structural emphasis. The cam’s working surface curve directly influences the knitting process, ensuring smooth and efficient operations tailored to the desired fabric design.

For instance:

Fine-knit fabrics may require precise and delicate cam curves.

Heavy or structured fabrics might need robust and durable cams to handle higher tension and strain.

Collaborate with fabric designers to identify the cam specifications that align with the intended design goals.

2. Choose High-Quality Materials

Given the high-speed sliding friction and occasional high-frequency impacts cams endure, material selection is paramount. The preferred material for cams is Cr12MoV steel, known for its excellent hardenability and resistance to deformation. This material offers the following advantages:

Durability

Handles prolonged wear and tear.

Hardness

Quenching hardness typically falls within the range of HRC63.5±1, ensuring optimal performance.

Strength and Toughness

Withstands the mechanical stresses of the knitting process without compromising on flexibility.

Avoid cams made from substandard materials, as they are prone to deformation and can lead to machine failures.

3. Ensure Optimal Hardness

Cam hardness is a critical factor that affects performance and durability. While the standard hardness is HRC63.5±1, deviations can have adverse effects:

Excessive Hardness

May lead to brittleness, increasing the risk of cracks or breakage.

Insufficient Hardness

Can result in rapid wear, reducing the cam's lifespan and affecting knitting quality.

Always confirm that the cams meet industry-standard hardness specifications to maintain the balance between durability and performance.

4. Focus on Surface Roughness

The surface roughness of the cam curve is a vital indicator of its quality. Smooth cam curves ensure minimal friction and wear on needles and sinkers, contributing to longer machine life and consistent fabric production. A rough or poorly finished cam surface can lead to:

Needle Damage

Grinding or wearing of needle heels.

Overheating

Excessive friction causing corner seats to heat up.

Operational Issues

Increased risk of machine malfunctions.

The industry standard for cam curve surface roughness is Ra ≤ 0.8µm. This metric depends on various factors such as processing equipment, cutting tools, and manufacturing techniques. Ensure that the cams are processed with precision equipment to achieve the desired smoothness.

5. Inspect Key Design Features

In addition to the curve and surface finish, it’s essential to examine other design aspects of the cam:

Hole Position and Keyway Alignment

Misalignment can cause operational inefficiencies or damage to other machine components.

Relative Position and Accuracy

The relationship between the cam’s shape, curve, and keyway must be precise to ensure proper synchronization during operation.

Even minor inaccuracies in these features can lead to significant performance issues, so attention to detail during inspection is critical.

6. Beware of Low-Quality Cams

Low-priced cams may seem cost-effective initially but often compromise on essential quality attributes such as material, surface finish, and precision. Substandard cams can:

Shorten Machine Life

Cause excessive wear on needles, sinkers, and other components.

Increase Maintenance Costs

Frequent repairs or replacements add to operational expenses.

Affect Fabric Quality

Lead to defects such as uneven loops or broken threads.

Always prioritize reputable manufacturers with proven track records for producing high-quality cams.

7. Regular Maintenance and Inspection

Once you’ve selected and installed the appropriate cams, ensure their longevity and performance through regular maintenance. Periodically inspect cams for:

Signs of Wear

Look for scratches, rough spots, or deformities on the cam curve.

Proper Alignment

Check that all components remain correctly positioned relative to one another.

Lubrication

Apply suitable lubricants to minimize friction and prevent overheating.

Routine maintenance helps identify potential issues early, preventing costly breakdowns and ensuring consistent fabric production.

Conclusion

The cam is a vital component of circular knitting machines, influencing both the machine’s efficiency and the quality of the finished fabric. Choosing the right cam involves understanding fabric requirements, selecting high-quality materials, ensuring appropriate hardness, and focusing on precision and surface finish. By paying attention to these factors and avoiding low-quality options, manufacturers can optimize their knitting machines for long-term performance and superior fabric production.

Investing in well-made cams not only enhances machine durability but also reduces maintenance costs, ensuring a smoother production process and better overall results.