Single-pass bore finishing

For many hydraulic and automotive honing applications, Engis superabrasive single-pass bore finishing is said to offer the best of both worlds: high-precision tolerances in a large-scale production environment. Development over many years has led to significant advances in bore size, geometry and customisable surface finish, so much so that bore size control has now reached the limits of current air-gauge capability.

Engis’ single-pass process uses a combination of superabrasive-plated tools, pre-set to exact dimensions, which pass through the bore, rotating as they complete the honing operation. The number of tools required for any specific task depends on: the amount of material removal required, the surface finish and the specified final geometry: roundness, concentricity, bow and/or size.

In the real-life example of a steering housing it was determined best to hold the part rigid and float the tooling, so spring-loaded holders provided the radial float for the tool assemblies, together with a special, free-pivoting union inside the tool mandrel. Up to 0.038 mm of ductile iron required removal and, as the bore had limited clearance at the bottom, it was necessary to deploy a semi-blind bore-finishing tool.

The tooling progression consisted of a series of six tools ranging from 40/50 down to 200/230 mesh diamond. Tolerance was within a total range of 0.7 µm, including variation in bore shape, and overall gauge accuracy and repeatability.

Using the single-pass process, it is possible to maintain tool size for relatively long periods of time, making it highly successful in the example of the steering housing. However, it is important not only to monitor and control the size of the final finishing tool, but of each tool in the progression.

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Post-processing of printed parts

The new 400 sq m technology and test centre of AM Solutions, a brand of Rösler, is outfitted with state-of-the-art engineering software and various 3D printing systems. However, the main focus at the facility in Untermerzbach, Germany is on an exceptionally well-equipped post-processing section, where AM Solutions 3D Post-Processing Technology can demonstrate an impressive range of machinery for finishing 3D-printed components.

Manuel Laux, head of AM Solutions 3D Post-Processing Technology, explains: “It is our declared goal to develop the best process solutions for our customers. To do this we must fully understand every detail of the additive manufacturing process and be in a position to demonstrate the various production stages. Only with such a hands-on approach will we be able take into account all the facets of additive manufacturing.”

Metallic materials at the test centre are printed with an EOS M 290 system, whereas for the creation of plastic components a Polyjet Objet 260 Connex 3 from Stratasys, an HP Jet Fusion 3D 5200 and a FDM printer are available.

To allow test trials for the development of optimum, automated post-processing solutions, and to select the most suitable equipment, AM Solutions 3D Post-Processing Technology has installed its own post-processing equipment line in the form of the S1, S2 and S3 models, as well as the M1, M2 and M3. Moreover, the test centre is equipped with various post-processing systems from partners of AM Solutions, including Gpainnova and PostProcess Technovlogies. These encompass a Gpainnova DLyte 100 and the first installation in the world of a DLyte 10,000. In addition, the Demi, Deci, Deci Duo and Rador from PostProcess Technologies are available for test trials.

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Cutting edge for Whiteley & Sons

A Sheffield-based scissor manufacturer that supplies royalty, Formula One teams, golf courses and bulletproof jacket specialists has invested in three new machines to help it meet an unprecedented rise in sales.

William Whiteley & Sons, which has been trading for more than 260 years, has spent in excess of £80,000 in upgrading its production capability to include state-of-the-art vibratory finishing technology.

Boosted by a capital grant from the Manufacturing Growth Programme (MGP), the latest addition brings automation to the company for the first time, helping it redeploy crucial labour to more value-added work and provide a 30% increase in capacity.

“When it comes to producing scissors and shears, we have some of the best craftsmen and women in the world,” explains company director Jeremy Ward. “We needed to protect those skills by investing in new technology that would automate a labour-intensive, low-skilled process, and that’s why we pressed the button on the capital spend.

“The vibratory finishing machine provides repeatable quality and the option to manufacture through the night,” he continues. “It also gives us the smoothest and most aesthetically pleasing finish possible, which is what customers for our scissors and shears demand. Sales in this arena now account for 30% of turnover and our beautifully crafted products are being used by tailors on Saville Row, by major fashion labels and by the army of people who are turning to crafts during COVID-19.”

William Whiteley & Sons, which employs 15 people and boasts a £1.1m turnover, has been working with the Manufacturing Growth Programme to identify and overcome production bottlenecks.

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Total Carbide opts for Micromatic

Master Abrasives has installed a Micromatic Pluto 18 grinding machine at Aylesbury-based Total Carbide, a manufacturer of sintered tungsten-carbide wear parts.

Total Carbide was looking for a cost-effective new machine for its tungsten-carbide measuring probes. The component has a chamfer on the front corner which was ground by interpolation on the company’s previous machine.

Required stock removal on the measuring probe is 0.5 mm on diameter, while surface finish is 0.4 Ra with an outer diameter and length tolerance of ±0.25 mm. The new machine had to accommodate a volume of 2000-3000 pieces per month and it was necessary to have a Fanuc CNC to grind OD, face, chamfer and corner radius features, allowing a smooth transition for operators.

Micromatic’s Pluto-18 is best suited to the production of accurate, small components, and can perform both plunge and traverse grinding operations. Several features of the machine identify its suitability for the batch production of shaft-type components with a maximum wheel outer diameter of 400 mm (50 mm width). For instance, a rigid anti-friction wheel head is utilised for better geometrical accuracies, while an integrated table provides higher rigidity.

The Pluto-18 measures only 1.66 x 2.2 m, which can help to save nearly 30% in space compared with the footprint of a similar hydraulic grinder. Furthermore, the machine’s customised user-friendly graphics aid machine setting and operation.

Master Abrasives can show Micromatic machines in action at its grinding and finishing showroom in the Midlands, along with superfinishing devices, metrology equipment and abrasives.

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Calling on tool production expertise

Machines from both Walter and Ewag, and nowadays especially Ewag’s Laser Line Ultra and Laser Line Precision models, have consistently proven effective in the manufacture of successive generations of new mobile phones – producing tools from 1.8 to 8 mm diameter to machine the plastic or metal cast housings.

Very often – says Walter Ewag UK, a member of the United Grinding Group – the die-cast moulds are machined using tools produced by Walter Helitronic tool grinders/erosion machines and Ewag laser-based tool-manufacturing machines.

These so-called 3C tools (tools for computer, communication and consumer electronics) also now embrace PCD types. On the Apple iPhone 6, for instance, the bevel on the aluminium housing is machined using PCD profile cutters produced on Ewag laser-based machines. However, on the iPhone X, stainless steel is integrated into the housing frame, so CBN cutters (also produced on Ewag laser machines) are used rather than diamond-coated tools.

With new demands on design and technology, materials such as glass and ceramic are increasingly specified. However, due to their brittleness, hardness and low thermal conductivity, glass and ceramic place particular demands on the tools needed for machining. As a result, Ewag regularly receives customer requests for 3C tools with highly specific geometries – tools that are capable of producing very small internal radii and shoulders, as well as tiny turned parts.

In conventional tool manufacture, such tools would have to be manufactured and assembled from a variable number of parts but, using a Laser Line Ultra machine, for example, they can be produced fully automatically in one set-up.

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