The production of hand-held measuring equipment often means large batch runs and high demands on product accuracy. In this context, the selected manufacturing technology is faced with the challenging task of working at speed and with a high degree of precision. With this in mind, the solution chosen by Helios-Preisser in Germany is aided by Blum touch probes, which are used in the company’s machining centres for integrating continuous measurements into the process.

In 2008, Helios-Preisser, a manufacturer of hand-held measuring equipment for professional use, became aware that the capacity of its three machining centres was no longer sufficient. The company was operating around the clock in three shifts to manufacture its micrometers, vernier calipers, dial gauges, and marking and measuring instruments. Due to its positive experience with the company’s existing machine tools, Gammertingen-based Helios-Preisser opted to continue relying on machine tools from Heller fitted with Blum Novotest measuring systems.
A 14-m long pallet magazine connects the company’s machining centres, which are supplied with clamped workpieces by a robot. Helios-Preisser employees already had many years of positive experience with Blum touch probes in the company’s previous Heller machining centres, which still operate with great reliability. As a result, a new Heller four-axis machine was also specified with a Blum measuring probe.
Only the company’s five-axis machining centre used a probe from another manufacturer, a fact that did not meet with great approval at Helios-Preisser. “Where possible, I endeavour to make regional purchases. In Blum, we have found a partner that can offer us high-quality products and corresponding service from a close distance – we like to have just one point of contact,” emphasises CEO Siegfried Lorch. “In addition, we have been extremely satisfied with the Blum touch probes for many years.” As a result, a Blum probe has since been fitted to the five-axis machining centre.

With 120 employees, Helios-Preisser uses TC50 and TC60 touch probes from Blum. The former transmit data via infrared, the latter via radio technology. Each touch probe is fitted on a tool holder and can be substituted if necessary in order to execute measuring tasks before, during and after machining. The infrared system can be used when line-of-sight can be guaranteed between the touch probe and receiver. A measuring system with radio transmission is installed on the five-axis machining centre, which reliably transmits the signals from the touch probe to the receiver – even when the line-of-sight is disrupted by the large swivel head.
Blum touch probes are used for a whole range of tasks at Helios-Preisser. For example, they check whether the workpieces are clamped correctly prior to the commencement of machining. “We also use the probe to measure the result of machining,” says Tobias Weber, foreman of the milling shop. “After casting, the dimensions of cast blanks are often very different, which is why, prior to machining, the position of the blank is captured using the probe, with compensation values for the NC program transmitted to the machine controller. Thanks to the Blum touch probes, we have been able to reduce the rejection rate for these components from 10% to 1-2%.”
Another example is the tailstocks of the company’s bench metrology centres. Here, a hole must be positioned accurately to 0.01 mm for a channel on the same part. Previously, there had always been fluctuations, often due to the temperature response of the machine. If the dimension was correct in the morning with a cold machine and shop floor, by noon, with a hot machine and warm weather, the dimension would be out of tolerance. The channel is now machined and measured before finally being drilled using the measurement data. This strategy enables the desired precision to be reliably achieved regardless of temperature.

The large volumes manufactured in Gammertingen require short cycle times, so measurement must not take too long. Blum touch probes are designed for maximum measuring speed and are not sensitive to coolant, which is simply pushed away by the high measuring pressure. Measurements can also be taken directly after machining.
“The touch probe is moved at a top speed of 60 m/min until close to the component; touching then takes place at up to 3 m/min – so not much time is lost,” reports Weber. “After machining, we check almost all fits using the Blum touch probe.
“Our manufacturing process has now become so precise that we no longer have to grind many parts. Previously, numerous components were milled with an allowance and then ground to the finished size in order to achieve the required precision for our measuring equipment.”
If a machine determines that a tolerance has not been held, the pallet is automatically removed and placed in the company’s pallet store with an inspection record. The next morning it can be inspected to determine where the fault is and, in the meantime, the machine can continue to process further pallets.
With respect to unmanned production, the touch probes from Blum have completely proven themselves at Helios-Preisser. “Overnight, and often for parts of the weekend, the machines run unmanned,” confirms Weber. “We only operate one shift, but we produce more than we did previously in three shifts.”
Lorch concludes: “The systems run reliably during unmanned operation, which relieves the pressure on us and makes it possible to manufacture the required volumes without needing a night shift. Blum probes are essential to unmanned operations, especially as we are also very satisfied with the service offered by the company.”
For further information www.blum-novotest.com

Zinc and aluminium high-pressure die-casting specialist, RD Castings, has used Japanese-built, high-speed, twin-pallet machining centres from Brother since 1989, and currently has nine of them adding value to its products in two machine shops in Mildenhall. Since the mid-90s, the 30-taper machines have replaced manual milling, drilling and tapping, which was both labour intensive and subject to quality variation.

Running the company are siblings Anthony and Michael Pateman, who were interested when Brother’s UK agent, Whitehouse Machine Tools, suggested they see a demonstration of the new ISO control with 12” colour LCD screen, the CNC-C00, a significantly faster and more user-friendly CNC system fitted to its latest machines.
After they visited the agent’s Kenilworth showroom and technical centre, they came away not only with up-to-date information on the new control’s capabilities, but also having ordered another Brother machining centre, a Speedio R650X1 with Nikken rotary 4th axis. It was not their intention before the visit, but the machine was so productive and such a good fit for RD Castings’ needs that they placed the order on the day and invested in a second identical model within six months.
Numerous facets make the machine particularly applicable to machining light castings, one being its outstanding speed. Workpiece changeover is completed entirely within the 3.4-second rotation of the twin-pallet ‘Quick Table’, while the 21-pocket magazine’s 0.9 second tool-change time, 50 m/min rapids in X Y and Z, and rotation of the 4th CNC axis, are carried out simultaneously.
The first tool is ready to cut the next component immediately it arrives in the machining area, and little time is wasted on each subsequent exchange of the cutter due to the rapid tool-to-tool time and spindle acceleration from zero to 16,000 rpm in 150 ms, with similarly fast stop time.
“The speed of tool change on the R650X1 mirrors that of our Brother 324N and R2A models, where the tool carousel encircles and travels with the spindle, which does not have to move away to pick up a new cutter as on the Brother TC32A and 32B machining centres that we also have on-site,” explains Michael Pateman. “It results in very high productivity that is enhanced by faster processing of existing programs in the new CNC-C00 control. For example, we recently reduced a 3.5-minute cycle by 20 seconds with no change to the original program. If we are machining say 20,000-off parts annually, the saving runs into thousands of pounds.”

Anthony Pateman pointed out another advantage of the R650X1; the generous axis travels of 650 x 400 x 305 mm in X, Y and Z. The table accepts RD Castings’ 500 x 350 mm base plates on the trunnion fitted to both machines, allowing multiple components to be fixtured for two- and three-axis machining, relieving the load on the 324Ns and R2As, which are always filled with work.
He adds: “There is a trend towards larger castings these days and we have just installed a 500-tonne casting machine to meet the requirement. In order to perform machining, the ability of the R650X1 to swing our 400 mm diameter parts in the rotary axis means that we are often able to finish these bigger castings in one hit and save on a second set-up operation, which hugely decreases the cost of production.”
To underline this comment, he points to a casting of about the size that used to need a second operation but is now machined in one four-axis process, saving 70p per part.
Simon Hale, CNC machine shop manager, stated that the productivity of another part – an aluminium die cast housing for the rail industry – has been nearly doubled using the larger machine compared with the other Brother models featuring similar tool carousels. Some 17 castings per hour were drilled and tapped using 12 tools on the latter machines, whereas with a trunnion fixture on an R650X1, 32 parts per hour come off the machine after each pallet rotation. Furthermore, just eight tools are needed.
The increase in output is partly because, by routing coolant at the uprated 30-bar pressure on RD Castings’ latest machines through an indexable-insert drill rather than employing a twist drill, it is possible to produce larger holes above 18 mm diameter in one spindle movement, rather than having to spot and then peck drill the holes multiple times.
Michael Pateman asserts that manufacturing costs are increasing in Asia while the lower pre-Brexit value of the pound is helping UK competitiveness.

He sums up: “By employing ultra-high speed machining techniques on 30-taper rather than 40-taper machines, with extensive use of PCD inserts clamped in dynamically balanced tool holders, the cost of producing a casting is now about the same in Mildenhall as it is in China – and we are winning back business as a result.
“The latest Brother Speedios with their larger working envelope have added considerable versatility to our shop floor, as they can economically machine anything from the simplest, smallest casting up to the largest and most complex. Productivity is also up due to the faster control and by allowing more flexible production planning.
“All of our Brother machines work flat out eight hours a day and their speed, accuracy and reliability are fantastic. Coupled with the high level of support from Whitehouse, it has been an unbeatable package for us.”
For further information www.wmtcnc.com

Mills CNC, the sole distributor of Doosan machine tools in the UK and Ireland, has recently supplied a new Doosan VC630 5AX five-axis machining centre, equipped with a Heidenhain control, to hi-fi design and manufacturing specialist, Linn Products.
The machine has been installed at the company’s factory in Glasgow and is being used to produce a range of precision parts for Linn’s music systems. These components include machined-from-solid aluminium enclosures that comprise a lid and base for the company’s range-topping Klimax systems.

Prior to investing in the VC630 5AX, the machining of these enclosures was subcontracted, and while this situation was satisfactory it had its drawbacks and was always considered to be temporary. The arrangement was superseded by Linn’s desire to become more self-sufficient and vertically integrated, with the decision taken to commence machining the Klimax metalwork in-house.
Explains Fraser Crown, Linn Products’ operations architect: “The more of our manufacturing processes we can bring in-house, the better able we are to manage, control, optimise and ultimately improve them. Linn does not mass produce products; every product we manufacture is built to order. This can potentially cause scheduling and delivery fulfilment issues when relying on subcontractors who, quite naturally, prefer to handle larger and more predictable batch-type work.
“As part of our commitment to continuous improvement, it was a natural progression for us to look at bringing machining processes in-house, such as those employed to manufacture our enclosures,” he adds.
To enable Linn to manufacture all its Klimax metalwork in-house, the company needed to acquire additional machining capability. Linn is certainly no stranger to CNC machining and, some years earlier invested in a three-axis Doosan DNM650 vertical machining centre from Mills to manufacture a range of parts. Since being installed, the machine, according to Crown, “hasn’t missed a beat” and is working near peak production.
With regard to its next investment, three key questions initially confronted Linn: what type of machine tool would best produce the enclosures; which manufacturer would be able to supply the machine, and what support could they provide; and how quickly could Linn develop a reliable and repeatable machining process?

Linn’s ‘milled from solid’ enclosures feature in both the Klimax DS and Klimax DSM streamers, the Klimax amplifier, Klimax Exakt, and the Radikal power supply for the Klimax LP12 turntable. The enclosures are machined (internally and externally) from individual solid aluminium billets. Internally machined features include a number of separate and isolated chambers (divided by walls) where audio/electronic circuitry and power supply units are housed separately. The back of the enclosures contain a variation of machined holes for output and input connectors and ports.
All exterior faces of the enclosure are machined to a mirror-like finish, with the top and bottom being finished using a large diameter fly-cutter (cutting) tool that is able to face mill the entire surface in one pass to produce a uniform finish. “Surface finish imperfections, however small, are not acceptable as they would show up after the enclosures have been anodised,” states Crown.
To meet Linn’s manufacturing imperatives and quality standards, the company researched the market to identify the types of machining centres available.
“We wanted the machine to meet our immediate and future requirements, which is why we looked at large-capacity five-axis vertical and horizontal machining centres,” says Crown. “Although we do not machine parts in high volumes, flexibility, reduced set-up and cycle times, which are key advantages of five-axis machine tool technology, are important to us.
“We ultimately decided on a vertical machine with full five-axis simultaneous machining capability because it enables each side of the billet to be produced continuously without the need to remount the job,” he continues. “As a result, we negate any incremental dimensional inaccuracies and poor finish quality. We believe it will provide us with far more flexibility going forward. Furthermore, for certain machined features, most notably where the front panel display is located on the enclosure lid, we knew that using five-axis simultaneous machining capabilities would enable features to be machined reliably and accurately. In reality, the seamless five-axis movement which creates the ‘Klimax smile’ is dimensionally perfect, has a faultless finish and it is a joy to watch being machined.”

Linn already had a good relationship with Mills CNC following its investment in the Doosan DNM650 vertical machining centre five years ago. Discussing its latest requirements with Mills’ sales and technical staff, Linn decided to invest in a large-capacity VC630 5AX machine with Heidenhain CNC.
Owning a large-capacity machine means that Linn can produce a wide range of components – big and small. The decision to opt for the Heidenhain control (favoured by many mould tool and die makers) was taken for its ease of use and on-board functionality – especially its ability to help machine complex 3D surfaces and curved contours. The VC 630 5AX has a large working envelope (650 x 765 x 520 mm in XYZ), and a 32 kW/12,000 rpm direct-drive spindle.
Bringing any machining process in-house means there is an inevitable learning curve. Add to that the need to get to grips with the Heidenhain control (Linn’s Doosan DNM650 machine is equipped with a Fanuc control), and the curve becomes naturally steeper. However, the skill and experience of Linn’s operators and programmers, combined with technical and applications support (including training) provided by Mills CNC, has helped the company develop a secure and reliable machining process for its enclosures. Further refinement to fully optimise the process is ongoing and part and parcel of Linn’s continuous improvement ethos.
Concludes Crown: “The new machine is working well and we have found that having five-axis machining capability in-house makes us more productive and flexible. We are also able to respond, from a machining perspective, much more efficiently and effectively with regard to product design upgrades and modifications.”
For further information www.millscnc.co.uk

Rapid prototyping is often regarded as being synonymous with additive manufacturing (commonly termed 3D printing) technologies. However, a compelling case can also be made for CNC machining and injection moulding as rapid prototyping technologies, at least argues Stephen Dyson (pictured) of Telford-based specialist rapid prototyping provider Proto Labs.

Increasingly, rapid prototyping is a strategic capability. Being the first to market with a new product or refinement confers a competitive edge, and being able to quickly develop prototypes gives an important advantage in that race to be first. And once earned, a reputation for innovation leadership tends to stick: customers will defer buying decisions until they have had a chance to see the offerings from those businesses with a track record of delivering market-defining products and product enhancements.
For certain projects, rapid prototyping is a management discipline. In the race to be first, there is no point having roadblocks or bottlenecks in key design and development processes. And the more strategic an end product is, the more important it becomes to make sure that prototypes and their designs do not loiter at the back of the queue.
But rapid prototyping is also a technology decision, and as rapid prototyping increasingly moves centre-stage in the push to be first to market, that technology decision is becoming increasingly important.
Put another way, the selection of the wrong prototyping technology can have a lasting and damaging effect on both time-to-market and product quality or reliability. This is because, in a world where rapid prototyping is often synonymous with the use of additive manufacturing technologies of various types, manufacturers are in danger of becoming overly reliant on it as a prototyping technology. Sure enough, 3D printing might well deliver a part that helps check form, function and fit, but where a project requires other critical attributes, such as suitability for pre-compliance testing or customer validation, other prototyping processes may be more suitable.
Prototypes manufactured using a standard 3D-printing process are produced undeniably quickly, but the resulting plastic parts may have poor strength. Stereolithography (SL) and selective laser sintering (SLS) technologies are processes that produce strong parts, but they are not always suitable for functional testing, and may provide limited data on manufacturability. In addition, parts produced through SL tend to become brittle over time, while the surface finish of parts produced through SLS tend to require additional aesthetic enhancement.

Rapid prototyping through direct metal laser sintering (DMLS) and fused deposition modelling (FDM) is generally regarded as a significant improvement in terms of physical strength, the resulting prototypes being made of various metals (in the case of DMLS) or industrial-strength resins (FDM). But as additive manufacturing processes go, FDM is quite slow and produces parts with a potentially unacceptable surface finish, while DMLS-produced parts can be expensive if requirements call for more than a handful of components. And again, indications of finished-part manufacturability are comparably limited.
In short, while additive manufacturing technologies are ideal for producing parts with extremely complex geometries that will permit the checking of form, fit and function, in many cases, post processing (such as CNC machining of certain surfaces) enhancements may be required to meet the needs of the project.
So what does that leave in terms of rapid prototyping technologies? The answer, perhaps surprisingly, is CNC machining and injection moulding; technologies that are often generally regarded as being mainstream production processes.
In both cases, the resulting parts will have the same physical properties and surface finish as the finished part, and will generally provide excellent indications of manufacturability. In short, if an important aspect of the overall development process involves testing the physical properties of parts, then a convincing case can be made for rapid prototyping through CNC machining and injection moulding technologies, especially if the prototyping process calls for small batches of components, as opposed to one-offs.
Furthermore, again in both cases, it is very possible for these technologies to be genuinely rapid. Both are capable of extensive digitisation, with the time taken to produce an injection-moulded part being further reduced by machining the requisite moulding tool from aluminium rather than steel. In short, coupling CNC machining and injection moulding as a prototyping technology may take a little longer than with additive manufacturing, but can yield vastly more useful data in terms of the conformance characteristics of the prototypes in question, as well as their manufacturability. Plus, the added cost is spread as the number of required prototypes increases.

Even so, this is not to say that there is no place for additive manufacturing within a prototyping strategy. Of course not. It is simply that a well thought-out prototyping strategy is likely to be one that embraces several rapid prototyping technologies; additive manufacturing to start with, in order to provide initial data on form, fit and function, before moving to CNC machining or injection moulding as appropriate for subsequent rounds of prototypes. The acquired data will then provide the necessary confidence to invest in the CNC machining or injection-moulding process.
Ultimately, the decision process is more complicated than a policy of using only 3D printing technology. However, as rapid prototyping becomes an ever-more strategic capability, deciding which technology to employ is increasingly worth in-depth consideration. So, if an OEM discovers that its rapid prototyping provider cannot support digitisation together with CNC machining and injection moulding capabilities, then it could be time to look for another provider which does.
For further information www.protolabs.co.uk