TechArchive

Original article date: May 1999

The sensors and systems exhibition that comes to you…

Erwin Sick’s innovative sensors and systems are heading your way! The company has fitted out an impressive roadshow vehicle which toured Ireland, Northern Ireland and Scotland in April, and returns from a tour around the continent at the end of May. Throughout June and July the 1999 Erwin Sick Roadshow will be traversing the length and breadth of England and Wales, parking at convenient locations and making it easy for you to examine and discuss the latest developments in industrial sensors, barcode reading systems, laser measurement and safety components.

With fewer and fewer engineers now able to afford complete days out wandering around trade shows, an exhibition which comes to your town – or even your company site – is proving to be a very convenient alternative.Once on board, you’ll be able to see working displays of some genuinelyinnovative products including:

The DMH Dimensional Multifunctional Height Sensor -  laser profile measurement, an economical alternative to camera vision systems.

The PLS/LSI Programmable Laser Scanner – 180deg scanning of a safety detection area with interface allowing up to eight safety zones.

The LMS Laser Mesurement System – for volume or level measurement, anti-collision applications, object classification, etc.

The CLV430 Bar Code Reader with SMART technology – revolutionary software decoding allowing the reading of misaligned, dirty or partially damaged bar codes.

There’s also a clever model of a factory production area showing a mix of Erwin Sick products in a practical environment, as well as presentations on safety risk assessment and bar code reading.

The planned route of the 1999 Erwin Sick Roadshow ison this web site. Its specific schedule is constantly being updated as engineers request new stops at their company, so to find out the time and place of the Roadshow’s nearest visit to you, callAnn WhiteorAndrea Hornbyon 01727 831121.

• Erwin Sick Ltd.
  Waldkirch House
  39 Hedley Road
  St.Albans
  Herts
  AL1 5BN

• Telephone 01727 831121

• Fax 01727 856767

May 1999

Original article date: October 1999

Fewer and simpler components in the company’s vacuum pumps is the result of ASF Thomas’ foray into DFMA design principles. Alan Quinn reports

Going back to first principles and looking at pump design from the ground up using DFMA (design for manufacture and assembly) was the starting point for ASF Thomas in developing its latest range of vacuum pumps.

Using the capabilities of three sites in the US, Germany and the UK, the goal of the development programme was to design a range of pumps which would lend themselves to fully automated assembly, or make more effective use of semi-automated production techniques or manual assembly methods.

Amongst the key areas explored were:

• How to design parts so that they cannot be assembled in any orientation except the correct one
• How to reduce the number of screws or eliminate them completely
• How to minimise the number of parts in any pump design.

A number of new production techniques emerged from the programme, including “snapper” technology, which allows products to be snapped together instead of requiring screws, nuts and bolts.

The first two products to emerge from the development programme were the LM22 and 5003 pumps. The 5003 emerged from the development of a pump specifically designed for a market-leading electrical appliance manufacturer. During a four-month development phase, ASF Thomas produced a pioneering membrane pump consisting of just eight parts and a single screw.

The pumps is assembled from its key elements – connecting rod, diaphragm, valves and gasket. The design of the drive bearing has been radically simplified also, and to ease assembly, the pump head is equipped with a tried and tested clip fastener.

In contrast, the LM22 was developed as a universal pump. It is a low noise design, intended for the widest range of applications which can be achieved at minimum cost. Fully adjustable without increasing pulsation, a vibration damping version is available and the design allows a DC version to be offered at minimal added cost. A low cost suspension has been developed, with a accessories including a connection manifold with integrated noise damper.

• ASF Thomas

October 1999

Original article date: May 1999

A fluid amplification technique from the oil and gas industry could soon be cleaning your lounge carpet. Alan Quinn reports on the latest Hoover development.

No bags to buy…no replacement filters to buy…that’s the proposition offered by the Hoover Vortex vacuum cleaner available this month to the electrical trade.

The Hoover triple Vortex system separates dirt particles from the air using centrifugal force in a multi-stage cleaning process. It is a form of fluid amplication whereby fine dust is continually scrubbed from the transport air over and over again. Whilst the principle of a bagless cleaner is not new the Vortex goes further and includes stages where the air is finely cleaned. It is this process which prolongs the life of the filter as the final stage is a further cleaning in a high efficiency vortex. And if the air is not clean around it goes through stages two and three again.

Hoover teamed up with BHR Group engineers at Cranfield. The cyclone technology known as amplified spin-cleaning was originally developed for the oil and gas industry. A compact in-line device known as Wellsep used to separate gas from crude oil was miniaturised at BHRand this was the starting block for the development of the Hoover Triple Vortex separation system.

The new separator comprises an entirely novel multi-stage vortex arrangement with a built-in or feedback loop. Three stages cooperate as follows: a first stage vortex is induced in the dust container which spins our more than 90% of the dirt. Semi-clean air is then drawn into a second-stage involute separator which induces a high velocity vortex to concentrate fine dirt into about 20 of the air flow. This portion of the flow is then cleaned using a third stage miniature cyclone – smaller cyclones generate higher g forces and are better at removing the finest particles. Transport air from the third stage is re-injected into the second stage vortex for a final “scrub” before exiting perfectly clean.

• Hoover European Appliance Group
• Caroline Knight
• Tel: 01685 721222

• BHR Group
• Dr Matt Davies
• Tel: 01234 750422
• http://www.bhrgroup.co.u k

May 1999

Original article date: June 2000

Pilz’s Pipanel Touch is now used at Triumph to calculate shim sizes required, specific to each engine against default sizes.

Thunderbird, Daytona and Tiger… To any discerning motorcycle enthusiast, these names conjure up a unique image of highly desirable, technologically advanced motorcycles. In a word, Triumph.

With its sophisticated engine systems, combined with attention to detail and a commitment to quality, Triumph ranks as a top name in the British motorcycle industry, and worldwide.

Based in Hinckley, employing over 600 staff and producing 100 motorcycles per day, Triumph is one of the British success stories of the 90s. Production lines are automated wherever possible and are as advanced as any in the world.

One way in which production has been streamlined is in the shim-sizing process for camshafts in the engine. Previously the size of the default shims was calculated manually and shims were measured to fit particular engine models. Shim sizes often had to be re-calculated, the shims removed, re-sized, re-measured and refitted until a perfect fit was achieved. This had always been something of a laborious process taking two people as many as four cycles per shim.

The solution to the problem lay in a high-performance industrial computer which could be used for telemetry purposes and would be compatible with the software designed by Triumph. Specifications would also have to include a touchscreen which could be easily navigated when wearing gloves, and would offer a clear bright screen together with a housing resistant to the chemicals and minerals found in engine oil.

Pilz’s Pipanel Touch is now used to calculate shim sizes required, specific to each engine against default sizes. Default shims are fitted into the engine as standard at the start of the process. The operator measures any differential that may occur. Results are input into the computer and the correct size required to make up the differential is calculated automatically. This method has eliminated the need for the re-checking and re-calculation process which previously was performed manually. Pipanel Touch operates using in-house, DOS-based software. And since Triumph has installed the industrial PC, the program has been further amended.

• Pilz

June 2000

Original article date: October 1999

An innovative positioning unit has the motor and drive close-coupled. WAYNE BROWN finds out the implications

On the face of it the Icla positioning drives look like a motor of some sort, having a shaft, a body and a cable entry. But take a closer look and you will see that SIG Positec has squeezed a gearbox, motor, encoder, power stage, microprocessor and fieldbus interface into a single unit.

What this means is that, given a fieldbus and central controller, you can download an instruction to the Icla drive and it will then move to the required position and stay there until it receives the next instruction. Indeed, you will notice that there is no mention of a brake so far, and that is because the high holding torque of the brushless DC motor is sufficient to maintain the position under normal conditions. However, if there should be a disturbance, the drive’s real-time position correction will come into play and bring the drive back into position.

One of the most obvious advantages of this all-in-one configuration is that you no longer need to find cabinet space for the motor controller. Time and money can also be saved because of the simplicity with which the integrated unit is mounted. In terms of electrical connections, all that is required is a bus link and a suitable power supply.

Of course, the bus link is bidirectional so, as well as sending instructions to the drive, the central controller can also receive diagnostic data. SIG Positec supplies a software package with the Icla units so that configuration, operation and remote diagnostics are made as quick and simple as possible.

Despite the innovative configuration, there have been no compromises on accuracy or torque – either running torque or holding torque. Four different gearbox options are being launched, giving nominal speeds of 30 to 220rpm and nominal torques from 3.5 to 12Nm.

Typical applications are anticipated to be in the fields of printing, packaging, and the wood, metal and plastics processing industries where ‘push-button’ format adjustments are frequently required on machines.

We have already seen several motors introduced with inverters mounted on their bodies, but we certainly like the look of this fully integrated positioning drive.

•  SIG Positec

October 1999

Original article date: April 2000

A new drive server has been launched promising to save programming and commissioning time for drive systems. Tommy Miller reports

Imagine a situation where there is an inverter drive, a machine interface and a PC linked to the drive so that data can be collected for analysis in, say, Microsoft Excel. The PC can easily be used to write the PLC program for operating the drive, and for programming the machine interface to display the desired screens and to react to the user inputs.

Easy, so far. However, the machine interface and the drive both need to communicate with each other, which might not be so easy to achieve, especially if the two come from different manufacturers. Also, there is a need to define the data sets separately for the drive and the machine interface, and errors can occur here that may take some considerable time to find and resolve.

“There must be a better way,” came the cry from the engineers at Lenze (formerly known in the UK as Simplatroll). So now the company has launched the drive server and this new software tool should make life far easier. Similar in concept to a printer server, the Lenze drive server is an OPC-based interface that is installed on a Windows NT-based PC and instructed as to which fieldbus protocol to use. The drive server then recognises which drives are present and configures itself accordingly, building up a database of all the drive information. Parameter groups can then be arranged and named.

The main advantages of this alternative approach are that the data sets have to be declared once only, and that different fieldbus systems – perhaps serving different types of hardware – can access the database and communicate with each other, whether they are Can, Profibus, Devicenet or almost any other. Because the data sets are only declared once, there is a significant saving in programming time. Furthermore, the opportunity for making errors is vastly reduced, so the time taken up with debugging is also cut.

Lenze estimates that 30-40% of a typical drive project is spent on engineering the interfaces between the various items of hardware, and that a large portion of this time could be saved by using the drive server. After commissioning, further savings should also be possible due to simplified maintenance and upgrading.

• Lenze

April 2000

Original article date: October 1999

By only having to control one axis at a time, this new controller benefits from exceptional performance, as David Norris has been finding out

Some clever technology has gone into the new PM600 digiloop motion controller which Mclennan Servo Supplies is launching. In particular, a new development of Mclennan’s control algorithm enables high positional accuracy to be achieved, but with zero deadband, even if remotely-mounted encoders are used for the positional feedback.

To enhance system stability, a dual encoder feedback technique has been used. Furthermore, the PM600 is equipped with three encoder inputs so as to allow this feedback technique to be used when one axis is to be slaved to another. In order to give the PM600 good repeatability, high-speed registration hardware has been used so that reference signals can be detected with zero error.

For cost-sensitive applications where motion is required in two axes, but not simultaneously, a single PM600 can be used to control both – hence the reference to a one-and-a-half axis controller. Nevertheless, with the PM600 priced at around (UK pounds)400, there will be many applications where it will be very cost-effective simply to install one unit per axis. Also, because the units are compact, there is not a significant requirement for cabinet space if multiple controllers are installed.

Despite its low price, the new controller is an extremely versatile device. For example, it provides both analogue and digital output signals, so it is suitable for use with either servo or stepper motors. And, in addition to bi-directional limit and datum inputs, there are 16 user-definable digital I/O and analogue inputs are provided to enable interfacing with other machine functions. Meanwhile, with operating speeds of up to one million counts per second and a positioning range of +/-2billion counts, the PM600 is a truly high performance motion controller. In many respects the exceptional performance and smooth motion result from the fact that the PM600 is a single-axis controller and the processor therefore does not have to supervise multiple axes. Loop control is therefore tighter, which results in zero error.

Apart from straightforward positioning, other standard control functions include electronic gearbox, flying shears and electronic cams.

•  McLennan

October 1999

Original article date: June 2000

Need a specialist bearing, but don’t know where to turn? Tommy Miller looks at a new range that seems to fulfil most unusual needs

Specialist bearings have traditionally come from a variety of sources, depending on whether the need is for resistance to high temperatures, corrosive fluids, vacuum, super-clean conditions, nuclear, non-magnetic components or high speeds. But there is now a range, known as Spacea, that fulfils all of these needs. Indeed, this range covers not only ball bearings, but also linear guides and ballscrews.

Developed by NSK-RHP, the Spacea range includes products that utilise high performance materials and coatings, and specialist lubricants have also been introduced. For example, as well as hybrid bearings with steel races and ceramic balls, there are also all-ceramic bearings that can be used in corrosive environments, air or vacuum, at temperatures up to 200degC. For other applications under vacuum, it may be appropriate to use the products that have gold, silver, lead or molybdenum disulphide solid lubricants. If the need is for a bearing to operate under vacuum and at high temperatures (up to 500degC), silver is the preferred solid lubricant.

One of the new lubricants that has been developed by NSK is the LG2 grease that is suitable for clean-room use. Compared with fluorine greases, LG2 is claimed to provide 10 times the life as well as superior corrosion protection. Depending on the other conditions, it may be better to use fluororesin-coated bearings and ballscrews, perhaps if there is also a vacuum and high temperature – as might be found in production lines for liquid crystal displays.

Other coating and plating options available for the steel Spacea bearings include cold fluoride chrome plating for improved corrosion protection, hard chrome plating or nickel alloy coating. This latter coating is said to provide the highest level of resistance to corrosion and attack from most acids, but at a very reasonable cost.

Applications for the Spacea bearings, linear guides and ballscrews will, inevitably, be extremely wide-ranging due to the vast array of materials, finishes and lubricants that are included. Nevertheless, it is fair to say that they are likely to be used in aerospace, semiconductor processing, the nuclear industry, medical equipment and many more.

• NSK-RHP

June 2000

Original article date: October 1999

We heard about an intriguing terminal box inverter that does not have to be mounted on the motor. Tommy Miller investigated further

Simplatroll believes that a typical application of the Lenze 8200 Motec terminal box inverter will have a payback period of under two years. There are several compelling reasons why this should be the case, in addition to the fact that an inverter will usually save energy costs if the motor speed requirement is not constant.

For an inverter that is mounted on or near a motor, rather than in a control cabinet, there can be an initial saving due to the reduction in cabinet space required. Then, because of the relatively high cost of shielded motor cables, there is another saving in hardware costs. Other savings result from the use of standard motor starter contactors (no chokes required) and local safety isolators (no electrolytic DC bus capacitors required).

There will be occasions where it is not desirable to mount the inverter directly on the motor, perhaps because of space restrictions. Nevertheless, the advantages of an inverter close to the motor are still attractive. Lenze has tackled this dilemma by supplying 8200 Motec inverters separately from the motors such that they can be wall-mounted if you prefer. The design of the heatsink means that the inverter will operate reliably in ambient temperatures as high as 60degC, with no need for forced airflow.

Lenze has spent a great deal of effort designing these new inverters to be high performance products. For instance, with a speed range of 1:50, the units are capable of driving a motor at its full rated torque as low as 1Hz. Speed control is achieved by means of sensorless vector technology.

Three-phase models are available in powers ratings from 0.55 to 2.2kW, but higher power versions are likely to be introduced soon, and single-phase models are also understood to be under consideration.

A few other features and options are also worth mentioning: first, an optional on/off switch and potentiometer can be fitted to the base of the Motec unit; second, there is an integrated PID function for process control; third, a built-in braking transistor removes the requirement for a separate brake chopper. Simplatroll can supply standalone Motec inverters, inverter motors and inverter gearmotors.

•  Simplatroll

October 1999

Original article date: September 1999

Developing a concept originally aimed at sealing liquids Feodor Burgmann has introduced a version of the CSR aerodynamic clearance seal for gases and gases containing solids.

The CSR type aerodynamic clearance seal consists of a split carbon graphite restricting ring that is held together by a tension spring around its circumference. Pockets are worked into the inner surface of the ring to generate a radial lifting force under operating conditions. A concentric gap thus forms automatically as the seal lifts off the shaft. Measuring no more than a few um this gap is small enough to keep leakage to a minimum. Good static sealing at standstill is guaranteed because the seal and the shaft are then in contact.

Now manufacturer Feodor Burgmann has launched a further development of this seal with a bi-directional gal lubricated version for gaseous media. It is suitable for all gas conveying machines such as gas turbines compressors turbochargers and turbo pumps. It can also be used with gases containing solid particles of grain sizes up to 10um. Liquid mist or flooding at standstill is withstood without damage as are radial movements of the shaft in the 0.1mm range.

The main advantage of this seal over comparable sealing elements for gases is that it achieves lower leakage rates whilst requiring the same installation space. For example its leakage is up to 50 times less than that of a labyrinth seal. Because a higher pressure differential is possible with a constant leakage rate the seal represents a simple form of differential pressure control for buffer gas systems. It runs together with the shaft but without making contact with it thereby enabling a machine to be shut down under controlled conditions in the event of a malfunction.

The cartridge design makes it easy to install. High sliding velocities are a feature: up to 200m/s cooled – ie with applied differential pressure) and up to 100m/s uncooled (unpressurised).

The operation of the CSR seal is independent of temperature in that the leakage rate remains almost unchanged throughout the entire temperature range (up to 500degC). Good emergency running properties are provided by the carbon graphite.

• Feodor Burgmann
• Ellen Neubarth
• +49 8171 23 14 53
• www.burgmann.com

September 1999