The Guide To Avoiding Common Precision Cutting Tool Mistakes

In precision machining, accuracy is everything. Even the smallest mistakes can lead to significant setbacks resulting in unplanned downtime, lost production and unexpected costs. Consistent, high-quality workpieces aren’t just the result of having the right equipment, they are produced when operators understand the nuances of how to use that equipment effectively.

This guide delves into the common pitfalls encountered when working with precision cutting tools, how to avoid them and how to get the most out of your equipment.

Micro-Machining

Micro-machining is a process, tailored towards extremely small components, which uses specialised CNC machines like the Kern Micro or Kern Pyramid Nano, combined with precision cutting tools, to cut and shape materials at the micro level. This is most often used in manufacturing components in watchmaking, micro mechanics, electronics and medical devices, where high precision in the micro scale is necessary. To achieve this, factors such as vibrations, tool alignment, and heat generation must be meticulously controlled, as even minor errors can go undetected at such small scales, resulting in significant consequences.

Reaming

Reaming is a precision tooling process to smooth and/or enlarge the interior of a bore to achieve an extremely accurate diameter and improved surface finish. Reamers are multi-faceted cutting tools, often with six-plus cutting edges arranged around their circumference to allow very small amounts of material to be removed consistently. They’re capable of achieving extremely tight tolerances, ideal for parts where hole size is critical for function and fit such as bushings, bearings and dowel pins.

Boring

Boring bars are used to either enlarge and finish the internal diameter of a pre-drilled or cast hole, or to create internal features inside a bore. They refine the hole’s dimension, roundness and surface finish and are used when standard drilling cannot meet a specific size or tolerance requirements. They can improve hole geometry, correcting imperfections left by the previous machining process and are important in applications where smooth contact surfaces are required such as hydraulic cylinders or precision housings where reaming is not necessary.

Dimensional Inaccuracies

Even the slightest deviation from specified measurements or tolerances can compromise functionality and fit, which is critical in high-precision industries such as medical devices, watchmaking, or aerospace. In the worst-case scenario, such errors could result in a scrapped component. This can happen for various reasons, including tool wear, but it may also stem from machine-related issues such as thermal expansion, improper workholding or toolholding setups, or incorrect speeds and feeds. These factors can lead to vibrations or poor surface finishes on the component.

All tools will inevitably wear out over time, regardless of how well they are maintained. However, this wear and tear can occur much faster if tools are used improperly or for the wrong application, or if regular maintenance and inspections are neglected. Using the wrong tool can lead to poor surface finishes, rapid wear and damaged workpieces. Similarly, a lack of maintenance will decrease precision and increase the risk of tool breakage. A dull tool cutting edge can generate excessive heat which can further damage the tool itself or even the workpiece.

Maintaining your cutting tools is essential to keep them in good working condition to ensure quality and reduce downtime. Here are our top tips for extending tool life:

Select the right feed rate and cutting speeds.

Use the right tool for the material. For example with harder materials a carbide or CBN tool will be more suitable.

Regularly inspect tools for signs of chipping, dull cutting edges and component surface roughness to identify tools which need replacement or resharpening.

Ensure proper tool alignment and minimise tool overhang.

Control temperature with coolants and lubricants to reduce heat generated during cutting.

Implement effective chip control such as chip breakers to cut them into shorter pieces and prevent them interfering in the cutting process.

Use tools built with anti-vibration features to help stabilise the cutting process.

Store and handle your tools correctly. Exposure to moisture might not effect the cutting tool but could cause corrosion of the tool holder.

You can have the best precision cutting tools in the world but if the materials they’re cutting are not up to scratch you will run into problems.

Always request supplier certification to show the raw materials meet the required standards and work with reputable suppliers who are known for providing consistent quality. Check for visible defects such as cracks or warping upon delivery and use calipers, micrometers and hardness testers to verify basic properties.

Depending on the application and industry you may need to use spectroscopy to analyse the composition, tensile and compression testing to measure the material’s strength and impact testing to determine its hardness.

Getting your cutting parameters right can dramatically reduce tool wear and tear and improve tool life. There are several things you should consider when doing this:

Material hardness – Harder materials typically require lower cutting speeds and smaller depths of cut to avoid excessive tool wear.

Thermal conductivity – Materials with low conductivity such as titanium retain heat when being cut so require lower speeds and effective coolants.

The right cutting tools - Hard materials usually need carbide or CBN cutting tools while softer materials are more suited to high-speed steel, sharp carbide tools or even ceramic tools. With very abrasive materials PCD can be the best option.

Determine the optimum cutting speed – This should be based upon the manufacturer recommended cutting speeds balanced with tool life. Higher speeds may increase productivity but can also increase tool wear.

Set the appropriate feed rate – This will depend on the material used, tool geometry and machine’s capabilities.

Adjust cut depth based on tool and material – Harder materials place more stress on the tool so reduce the depth to cut the load and minimise tool wear. For roughing operations a deeper depth can be used to remove a large amount of material rapidly. For finishing operations, reduce the depth to achieve higher precision and surface finishes.

Perform test cuts and analyse the results – Even if you think you’ve set everything correctly test the setup before proceeding to full production and make adjustments as necessary.

It’s frustrating when quality isn’t up to scratch but there are things you can do to identify the issue and improve cutting accuracy:

Excessive tool wear – Reduce cutting speed, use a more wear-resistant tool or coating and improve coolant application.

Poor surface finish – Replace or re-sharpen the tool, reduce the feed rate, minimise vibrations or adjust tool geometry for better cutting conditions.

Excessive chatter or vibration – Adjust the feed rate, reduce tool overhang and ensure both the tool and the workpiece are securely clamped.

Tool breakage – Check the depth of cut is not excessive and reduce as necessary, adjust cutting speed and feed and ensure your feed per tooth is not too high.

Dimensional inaccuracy – Inspect tools for wear and tear, replace worn tools, ensure machine stability and control heat build-up.

Quality control should be present before you even make a cut to ensure accuracy every step of the way. There are key measures you can take to ensure you consistently achieve precise results.

Start with thorough inspection and analysis of the raw materials to ensure they meet the specified standards for hardness and composition.

Next ensure the correct calibration of any CNC machines, lathes and other cutting equipment.

Implement a regular tool monitoring programme which tracks tool life.

Consider using real-time sensors to monitor vibration, tool wear and temperature as well as provide instant feedback.

Employ adaptive control systems or CNC machines which automatically adjust elements such as the feed rate, speed and depth of cut.

Speeds And Feeds

High cutting speed or tool rotation speed combined with too slow a feed rate can generate excessive heat, which will dull the cutting edges leading to tool deflection. Essentially, you will be rubbing and not cutting efficiently. The knock-on effect is the production of inaccurate parts and a poor surface finish. On the other hand, operating at too low a speed can lead to overloading, excessive chip accumulation in the flutes, and increased strain on the cutter, resulting in premature tool wear and potential breakage.

Optimising your speed based on tool type and material will lead to precise, consistent cuts.

Quality Of Carbide

Many different cutting tools are made from carbide but not all are created equal. At Rainford we only stock the highest quality tools. They may be more expensive to buy initially but their superior quality means they perform more accurately and last far longer when applied correctly. High-quality carbide with a uniform microstructure and optimal blend of tungsten carbide and cobalt binder provides sharp, durable cutting edges that can withstand the forces of machining without chipping or dulling quickly.

Service Process

Customer Tool Analysis: Customers are invited to send their cutting tools to Rainford Precision for in-depth analysis using the Keyence microscope. A detailed report is generated, diagnosing issues and providing tailored recommendations for improvements.

Pinpointing Root Causes: The high-resolution imaging enables the identification of specific tool wear characteristics, cutting parameter issues, or tool holding and concentricity problems. By pinpointing these root causes, Rainford Precision helps customers make informed adjustments to their processes.

Maximised Efficiency: Implementing these recommendations translates to reduced tool wear, enhanced productivity, and significant cost savings.

Services for All Cutting Tool Users

This service is accessible to customers across industries, including aerospace, medical, defence, motorsport, education, nuclear, and watchmaking:

For Existing Customers: A full diagnostic report is provided, detailing recommendations to optimise tool performance and extend tool life.
For Potential Customers: Rainford Precision analyses tools (irrespective of the manufacturer) and offers improvement advice. Additionally, customers receive a quote for tool solutions tailored to enhance their processes.

Why Use Our Service?

By combining advanced technology with years of industry expertise, Rainford Precision not only identifies tool issues but also offers actionable solutions to enhance machining outcomes. The service is particularly beneficial for industries in the high-precision and high quantity production areas, where even minor inaccuracies can have significant effects on the cost per component. This commitment to quality and innovation underscores Rainford Precision’s role as a leader in precision tooling optimisation.

Precision Solutions Backed by Expertise and Innovation

Rainford Precision’s long-standing commitment to excellence and innovation has made it a trusted name in precision engineering since its founding in 1991. With over three decades of expertise, our company has continually grown and adapted to meet the needs of a wide range of industries, including aerospace, motorsport, medical, and the nuclear sector. Proudly certified to ISO 9001:2015 standards, we are committed to delivering excellence at every level.

As industries continue to push the boundaries of what is possible, Rainford Precision remains steadfast in its mission to provide tools and services that meet the highest standards of accuracy, reliability, and efficiency. Whether addressing common cutting tool challenges or offering bespoke engineering solutions, Rainford Precision is uniquely positioned to support businesses in achieving their precision manufacturing goals.

For more information on how Rainford Precision can help optimise your machining processes, visit rainfordprecision.com or get in touch with one of our expert team today.

The Guide To Avoiding Common Precision Cutting Tool Mistakes

Introduction

Understanding Cutting Processes

Turning

Milling

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