Take the rough with the smooth How to improve the surface quality of automotive moulds?
Celebrating its 50th anniversary, Renishaw is set to attend EMO Hannover 2023 to showcase new products that enhance manufacturing performance accuracy and repeatability. One of the highlights is the NC4+ Blue non-contact tool setting system.
The plastics industry saw major growth after a wave of new synthetic polymers were introduced around the 1950s. The automotive industry was quick to benefit from the rise of these new types of plastic. Although plastics are now used widely throughout vehicle production, until this point, cars were traditionally made almost entirely out of metal. In addition to lower cost, other key benefits of using plastic in automotive engineering include its lightweight properties, durability and impact resistance. By the early-2000s, many previously metal automotive components could be replaced with high-performance polymers very effectively. This significantly reduced the weight of the components in an average car and led to a step-change in fuel efficiency.
As a result, injection moulding is now a leading method for manufacturing solid plastic automotive parts. The high-value moulds involved are costly to make but enable the mass production of high-quality, complex vehicle components in a single production cycle.
Accelerating electric vehicle development
As electric vehicles (EVs) cross further into the mainstream, powertrain electrification will present several key challenges for the automotive supply chain. Now, more than ever, EV designers are pursuing extended range through motor efficiency and battery effectiveness. As a result, the lightweighting and quality requirements of automotive components have never been more important.
Electric vehicle technologies will continue to be defined and refined over the next five to ten years, which means the demands on the mould tool industry will be significant. As EV designs evolve, automotive components will require continual modification and refinement. To produce the highest quality new mould tools, made right first time, and with minimal downstream finishing, fast, flexible and resilient manufacturing is required.
Upholding automotive standards
Precision mould design and manufacture is critical to the safety and performance of the automotive parts being produced. The surface quality of a mould tool, for example, is key to producing moulded vehicle components that can achieve the exacting standards required of the automotive industry. It can directly impact the functionality, quality, mould release, wear resistance and surface appearance of the moulded part. Today, using advanced manufacturing technologies to produce these automotive moulds is essential.
For over 50 years, global engineering technologies company, Renishaw, has worked closely with its automotive customers to solve key manufacturing challenges. The company is best known for the design, development and delivery of precision measurement and process control solutions for manufacturers. Its products have been used in and around the manufacturing industry since the 1970s — particularly for CNC machine tools and quality control.
Renishaw’s range of non-contact tool setters, for example, provides industry-leading tool measurement and broken tool detection. Let’s find out how this company — also a precision manufacturer in its own right — supports mould and die applications for the automotive industry.
Automotive mouldings can be complex, multi-part pieces with free-form surfaces. For mould and die applications, where multiple types of cutting tool are used to machine the surface of a single workpiece, tool-to-tool accuracy is vital. When switching between cutting tools, the length of these tools must be accurately set to prevent the creation of a ‘step’ on the surface of the mould. Such an imperfection would be reproduced on every subsequent component made using that mould and could compromise the performance of the part.
In CNC machining, cutting tool length errors can cause inaccuracies that result in machined features not meeting the required tolerances. Renishaw’s range of tool-setting systems provide high-precision, high-speed cutting tool measurement. Its NC4+ Blue non-contact tool setting system, for example, features high-accuracy blue laser technology for reliable cutting tool measurement. To further ensure the consistency of results, it also provides an integrated ‘air blast’ for the swift and efficient removal of machining debris and coolant from the cutting tool prior to measurement. Accurately set cutting tools produce smooth surfaces, not steps.
To determine the tool-to-tool accuracy of length measurement provided by the NC4+ Blue system, Renishaw uses a cutting test based on the ISO standard (ISO 230-10 22.214.171.124.3). When tested on a Makino D200Z 5-axis CNC machine tool, the tool-to-tool accuracy of the NC4+ Blue tool setting system was found to be as low as two microns.
Checking for tool defects
Optimum surface finish requires accurate tooling and machining to ensure performance and high-quality output. Machining with a chipped cutting tool is another scenario that could impact the surface quality of a mould tool. Poor surface finish can affect how easily a part is released from its mould. Parts formed from silicone or nylon, for example, could become stuck. Poor quality surfaces can also impede the flow of material into the mould, which could mean that additional finishing is needed, adding to the overall time it takes to produce the moulded part.
The cutting tool defect may be only tens of microns, but still produce noticeable imperfections on a machined surface. The non-contact NC4+ Blue tool setter can measure cutting tool length and diameter, and check for broken cutting tools. It can measure very small tool features for excellent tool-to-tool accuracy, and has a small in-machine footprint, minimising the space it occupies on the machine bed.
The NC4+ Blue system also offers an impressive suite of software cycles, which can be used to detect even the tiniest defects in cutting tools. This can help manufacturers to ensure the high-quality surface finish of their moulds. These easy-to-use software cycles provide an intuitive way of measuring a wide range of cutting tool imperfections which, if left unaddressed, could lead to poor surface finish. Supplied cycles include system calibration, cutting tool measurement on- and off-centre, cutting tool corner radius measurement and machine thermal drift measurement. Cutting tools can also be checked for broken or ‘pulled out’ conditions and damaged or missing cutting edges on tool radius or linear profiles.
The NC4+ Blue tool measurement system can perform high-speed checks that determine whether cutting tools are damaged, broken or have missing inserts or burrs. It can also scan up the cutting tool edge to detect chips as small as 30 microns in the tool flutes. Not only that, but the system can also measure cutting tools made from a wide range of different materials and those that use through-tool coolant.
When you’re confident in the condition of your cutting tools, you can machine complex, high-value automotive mould tools, right first time, with little or no downstream machining. Renishaw’s NC4+ Blue tool setting system can give you that confidence.
Renishaw’s range of non-contact tool measurement solutions can help to automate — and reduce the complexity of — previous manual tool setting activities. This means you don’t need decades of traditional manufacturing experience to set your cutting tools accurately and produce high-quality mould tools with smooth surfaces.
A range of user-friendly programming options add to the NC4+ Blue non-contact tool setter’s ease of use, eliminating the need for extensive knowledge of G-codes. Using Renishaw’s Go-Probe smartphone app, for example, you can create tool setting routines with just a few taps. Simply select the required cycle and enter your data to receive a single-line command, and then enter it into the CNC controller.
As well as fixed and separate non-contact tool setter system options, Renishaw also provides bespoke custom solutions to suit specific applications. With a range of sizes, mounting configurations and additional integrated probing systems, the NC4+ Blue non-contact tool setter is ideal for almost any application.
Your partner for innovative manufacturing
On April 4, 2023, Renishaw celebrated its 50th anniversary. Over the last five decades, the company has engineered numerous game-changing manufacturing innovations, which have had a significant impact on the business of making things and transforming global manufacturing capability.
To showcase its extensive range of technologies for more productive and sustainable manufacturing, Renishaw is attending EMO Hannover 2023 in Germany from September 18-23. The experts from Renishaw welcome visitors at stand B32 in hall 6, where its team will be showcasing a range of new products that deliver improved performance accuracy and repeatability, including a new line of products for industrial automation, and Renishaw Central, its new smart manufacturing data platform.