LowStir Friction Stir Welding System

March 11th, 2010

Friction stir welding is a welding process invented by TWI in 1991.  The process involves a spinning tool, in contact with the material to be welded, with sufficient down force to create frictional heat in the material (about 80% of the material’s melting point).  This causes the material to become soft, allowing the spinning tool to create the weld.

Friction stir welding is now widely used in the aerospace, automotive, rail and ship building industries.

Unlike other friction stir welders, the LowStir friction stir welding LowStir Welding Unit In Action - Image 1system includes a unit that attaches to most standard milling machines via an ISO taper, making it an affordable option to smaller enterprises.  It is supplied with software to calibrate the system, monitor the welding process and log welding parameters for later analysis.

The current LowStir base system comprises the necessary hardware and software to convert a suitable milling machine to a LowStir stir-welding system including an ISO taper (or equivalent) to fit it to the milling machine.  Since this depends on the particular machine, the size and type of taper must be specified when requesting a quotation (as costs of tapers can vary).

Benefits of Friction Stir Welding

  • Improved weld properties (e.g. strength, fatigue) compared to arc welding or riveting.  Joint efficiencies of 75-96% have been reported depending on materials.
  • Because it is a solid phase process (where the materials are joined without melting) no shielding gases or filler materials are required. Furthermore, there is almost complete elimination of weld distortion and solidification defects.
  • Operators do not need special qualifications or certification.
  • There’s no arc welding, gas emissions or weld spatter involved.
  • Vastly reduced preparation and reworking time reduces costs, time and labour requirements.
  • Low power consumption; The only energy required is to rotate the tool and apply force to it to create the frictional heat.  Without the large current requirements of arc welding, energy consumption can be reduced by 80% plus.

The LowStir System

Specifically, the basic components of the system are as follows:

1) LowStir Mk.2 sensor head unit including tool holder and heat shield disc.  This is supplied already bolted together as a complete system including the ISO taper, ready for installation in the milling machine head.

The LowStir unit is capable of measuring:

  • Down force (Fz) to 50kN
  • Lateral force (Fxy) to 25kN
  • Torque (Mz) to 100Nm
  • Temperature of the welding tool via an internal thermistor

The unit will run at rotation speeds of up to 3000rpm and log data at software selectable rates from 1Hz to 100 Hz.

2) Inbuilt battery.  When fully charged, the LowStir unit’s inbuilt battery has a battery life of approximately 10 hours.  The unit is supplied with a battery charger, which can recharge this battery from the mains.  The charger automatically deactivates when the charge is full, so the unit can be safely left to recharge overnight.

3) Jack plug switch.  The unit is also supplied with a jack plug switch which can be inserted to completely disable the unit and store any remaining charge.

4) Set of tool assemblies.  A typical assembly comprises a low wear shank and a replaceable tool (probe).  If you order one tool type there will be one shank and ten probes supplied.  If you order two different types of tool then there will be two shanks (one for each material to be welded) and five probes supplied for each of the two shanks.

5) Taper.  As mentioned above, the system includes an ISO taper or equivalent specific to the milling machine to which the LowStir is to be attached.  The size and type of taper required must be detailed in advance, and ordering the incorrect taper will make it impossible to fit the LowStir unit.

6) Software for monitoring and recording various parameters of the weld.  Note that the software is supplied uninstalled and uncalibrated.  We strongly recommend the optional laptop package, as this is supplied with the software and Bluetooth connection fully set-up and calibrated.  See Optional Extras below for more details.

Optional ExtrasLowStir Welding Unit In Action - Image 2

The following are optional extras that can be supplied at extra cost.  Please specify any extras required when requesting a quotation.

1) Internal temperature probe.  The system can be supplied with an internal probe which is used to monitor the temperature of the weld pool via a probe fitted to the inside of the welding tool holder.

2) Laptop. The software can be provided ready installed on a laptop computer.  In addition, the software will be calibrated for the specific LowStir unit, and the Bluetooth connections established between the laptop and the unit.  It is strongly recommended that this option is taken, as it means that the system is ‘plug and play’ and removes the need to calibrate the system on-site.

Licence

Please Note: Currently you will need a licence from TWI to carry out friction stir welding.  This applies to ALL forms of friction stir welding, including using LowStir.  Please contact TWI or David Johnson at Applied Measurements Ltd for more information.

Posted in Application Stories, Customised Sensors, Load Cells & Force Sensors, Torque Sensors | No Comments »

Custom Torque Sensors Now Available on Standard Lead Times

July 1st, 2009

dtd-s-200x200

A UK manufacturer of torque sensors is offering custom designed static/reaction torque transducers on similar lead times to its standard units, with only a small premium on the standard list price.

Applied Measurements Ltd, based in Aldermaston, is able to design and manufacture custom torque sensors to meet any customer requirement, including different flange diameters, unusual sizes of square drive, special sealed versions and shorter, more compact designs.

According to Peter Lewis, Managing Director at Applied Measurements: “Many manufactured products require fatigue testing to ensure that they can operate for a guaranteed minimum period of time.  An accelerated life test, for example, may be carried out on a drive shaft to determine the torque limits.  The fatigue testing can sometimes be an afterthought. If this is the case, some kind of customised sensor is then required before the torque sensor can be coupled to the test unit.  This is what Applied Measurements specialises in.”

Whilst Lewis concedes that there are plenty of companies able and willing to supply static (reaction) torque sensors from their standard range, many do not offer customised designs, let alone on lead times that are similar to standard product.

Applied Measurements manufactures two types of static torque sensor as standard, a square drive mounting type and a flange mounted unit.  The DTD-S square drive mounting sensor is designed specifically for measuring direct torque and is ideal for use in the calibration or testing of torque tools (screwdrivers, spanners, etc) in a quality assurance and inspection environments.  The sensor is constructed from stainless steel and is protected to IP65.  For fast, easy connection, the sensor is supplied with an integral, robust bayonet lock military connector.  The DTD-S is available from 10Nm up to 50,000Nm as standard, with custom versions rated to 200,000Nm.

dtd-f-200x2001The DTD-F range of flange mounting static torque sensors are also designed to measure direct torque, but are ideally suited to fatigue test applications.  Again, the units are finished in stainless steel and are protected to IP65.  The sensor is provided with an integral, robust bayonet ‘lemo’ connector for fast, easy connection.

As Lewis continues: “The flange mounting sensors are normally used in applications where there are two mating faces, one driving or applying the torque and the other resisting the torque.  For any torque sensor to work, there has to be a reaction or load to generate the resistance to motion and hence torque.”

“While we offer customers a range of standard torque sensors, we also have the ability to design and manufacture custom torque sensors, where the standard unit does not suit the application.  It could be the size and shape of the sensor that needs changing, but could also include the need for odd size ranges that fall between the standard increments.”

Lewis says this could include making the sensor longer, shorter, broader, or with different flange diameters and thicknesses.  Units with different hole spacing or with an odd size of square drive may be requested.  As an alternative to the square drive unit, Applied has also custom designed round shaft units with keyways.  By creating a tubular design and applying the gauges internally, it is possible to create high integrity sealed units for wet environments.  Other custom torque sensor designs have included two-axis measurement of combined force and torque, pressure-compensated models or complete submersion units.

Applied Measurements has supplied custom static torque sensors to a variety of customers and industry sectors, including aerospace, marine, oil and gas, robotics, machine building and plastic moulding machines.

Applied Measurements’ full range of static torque sensors can be seen here.  Alternatively, please call the sales department on 0118 981 7339 or email: info@appmeas.co.uk.

Posted in Customised Sensors, Product News, Torque Sensors | No Comments »

Custom Load, Pressure, Torque and Displacement Sensors for Machine Builders

May 1st, 2009

By providing custom design services for its range of load cells, torque sensors, pressure transducers and displacement sensors, Applied Measurements Limited is helping machine builders and systems integrators to reduce lead times, cut costs and improve quality.

“Despite the current economic downturn, we have grown our sales revenues by more than 30 per cent over the last three years,” says Peter Lewis, Managing Director at Applied Measurements Limited. “A major part of this growth is coming from our custom design service for our products, which include load cells, torque sensors, displacement sensors and pressure transducers. We are supplying one-off designs, pre-production prototypes, high volume specials, direct competitor equivalents, as well as modifying or strain gauging existing components.”

According to Lewis, many of Applied Measurements’ global customers now request custom designs on as fast a lead time as possible. “Rather than trying to make existing, standard catalogue sensors ‘fit’ their application, customers now seem to want custom solutions delivered in as short a time frame as possible. After all, there seems little point in offering a custom design service for your sensor if the lead time doubles as a result. Customers simply won’t wait that long. In most cases, we can deliver a custom solution – including concept design, engineering, production and calibration if required – in just six to eight weeks from customer order.”

In a tough economic climate, says Lewis, Applied Measurements has recognised that this ability to meet a customer’s exact design requirements on a competitive lead time, has given the company a clear edge on its competitors.

”Our design service not only includes the ability to design new custom sensors,” says Lewis, “but also includes manufacturing direct equivalents to existing competitor products, as well as retrofit versions that the competitor may have ceased to produce. It can also include the bonding of strain gauges to metal structures or housings provided by the customer and then completing these into a finished, certified and tested product.”

Machine builders and systems integrators often need to upgrade a machine for the end user, to include new electronics or instrumentation, from older mechanical gauges or dials. As Lewis states: “In this age of accountability, it is important to have sensors that are connected to the appropriate instrumentation, including PCs that log and record the measurement data, providing traceability for the end user. In these types of applications, there are usually physical restrictions that also need to be overcome, as the customer is likely to want minimal disruption to the original machine. This is where our ability to fit in with the existing design is a big advantage to the customer. Our combination of mechanical and electronics design capability also helps here.”

Many machine builders need their systems to measure in more than one axis at a time. For this, Applied can design two or three-axis force sensors, with a variation on this when customers want a sensor to combine two measurements, such as force and torque, or force and acceleration.

The aim of the custom design service is to provide customers with a solution that exactly fits their measurement requirements under the constraints of cost, size, environmental conditions, general performance specification and availability. As Lewis puts it: “An incorrectly chosen transducer to fulfill a particular measurement application costs considerable time and money if it is eventually discovered that the data being collected is meaningless, or that the transducer is performing incorrectly due to overloading or poor installation.”

“Our experienced application engineers will talk through the measurement requirements with the customer in order to determine the most appropriate solution. This typically includes discussions on the measurement range required; dynamic transient effects; space restrictions; accuracy levels; and whether there are any unusual environmental conditions to consider.”

For more information on Applied Measurements’ custom engineered solutions please contact our sales department on 0118 981 7339 or send an e-mail to info@appmeas.co.uk.

Posted in Customised Sensors, Displacement & Position Sensors, Level & Depth Sensors, Load Cells & Force Sensors, Pressure Sensors, Product News, Torque Sensors | No Comments »

New Range of Strain Gauge Based Displacement Transducers

April 15th, 2009

AML/SGD Strain Gauge Displacement TransducerApplied Measurements is pleased to announce the introduction of a new range of strain gauge based displacement transducers, the AML/SGD Series.

It is now available with stroke lengths of 0-5mm, 0-10mm, 0-25mm and 0-50mm.  The accuracy offered is +/-0.1% up to 25mm and +/-0.15% above 25mm, plus excellent long term and thermal stability.  They require a stabilised dc voltage excitation anywhere between 2 and 10 volts and return a high level millivolt signal proportional to the position of the plunger.

The AML/SGD Series are constructed using a rugged stainless steel tubular housing containing a spindle guide bearing and spring return mechanism.  A light spring force ensures a minimal effect on the application and enables inverted operation when required.  Precision construction guarantees a long service life with superb mechanical reliability.

The AML/SGD Series are suitable for a broad range of applications in Research and Development, Industrial, Aerospace, Civil Engineering and Automotive.  Being strain gauge based they are compatible with a wide range of analogue and digital monitoring, control and acquisition equipment found in both laboratory and field environments.

Posted in Displacement & Position Sensors, Product News | No Comments »

Underwater Load Cell offers Tension and Compression Measurement

March 15th, 2007

dden-200x200When approached by one of our customers to design a load cell for underwater tension measurement, We looked at our core range of products and decided the DDE style load cell, which features M12x1.75 male threads at each end, would best meet the customer’s requirement, but this model as standard is only rated to IP65.

With a small, quick and cost effective re-design we changed the construction to Stainless Steel with two halves locking together with a seal.  Internally it was further protected by back-filling with an inert waterproof gel.  The electrical termination is a tough IP68 multicore cable that is connected through an IP68 cable gland, to complete fully submersible sealing.

The new underwater load cell has been designated as the DDEN series.

By modifying an existing product we were able to keep the cost and delivery time down to suit our customers needs, whilst displaying our capability to modify or design a product quickly and efficiently.

Click here to view the DDEN Submersible Load Cell product page.

Posted in Application Stories, Customised Sensors, Load Cells & Force Sensors | No Comments »

High Volume, Low Cost OEM Strain Sensing Beam

April 10th, 2006

mini-strain-beam-200x200The requirement was to design and manufacture a simple strain sensing beam to fit into a very confined space and meet a stringent budget.  Following several months of design, development and creation the final product is manufactured from a high grade alloy steel requiring minimal additional machining.  A single strain gauge containing a full Wheatstone bridge is bonded to the beam in a specific position to maximise the sensitivity and accuracy.

During development a bespoke calibration system was also built to ensure that each strain sensing beam was accurately positioned and loaded for consistent quality.

Following the successful acceptance trials and approval by our customer, the strain sensing beam has been put into full production, which is expected to exceed 2000 pieces per year.

This is a typical example of our design, development and manufacturing capabilities in the field of bonded strain gauge technology.

Posted in Application Stories, Customised Sensors, Load Cells & Force Sensors | No Comments »

Strain-Gauged Chain Link Measures Tension in Poultry Plant Conveyor System

February 1st, 2006

gauged-chain-link-150x150The plant was experiencing severe chain wear problems causing loss of production.  It was suspected that this was due to excessive tension at certain points in the system.  The challenge was to identify these areas, which could only be done effectively in a live running situation.

Applied Measurements Ltd were supplied with a standard link from the chain, this was modified to enable strain gauges to be bonded to the structure, creating a strain-gauged chain link.  The transformation of the link into a load cell was completed by terminating with a four core screened cable, environmental protective coatings and calibration.

The strain-gauged chain link was then installed in the standard process chain and fitted with a portable data logger, this enabled the special link to map the forces around the system allowing adjustments to be made where required to ensure even tension, reducing chain wear and system stoppages.

Posted in Application Stories, Customised Sensors, Load Cells & Force Sensors | No Comments »

Bolt-On Retrofit Sensors for High Capacity Weighing Systems

October 5th, 2005

boss-f-200x200The BOSS series of bolt-on strain sensors from Applied Measurements provide a very cost effective solution for many high capacity weighing requirements such as on large tanks and silos, as well as finding application in overload protection systems on cranes, winches, lifts and presses.

The sensors are designed to be attached directly to steel structures and are capable of detecting tensile, compressive and bending stresses.

Utilizing the latest strain gauge technology, each sensor is manufactured from specifically selected high grade alloy steel with thermal coefficients of expansion matched to structural steel.  Unlike some competitive units each sensor is temperature cycled and compensated to minimize the effects of temperature variation.

For installation, each unit is supplied with a template to which the two threaded mounting blocks are attached using high tensile bolts.  The mounting blocks are welded in position and the bolt-on sensor then attached in place of the template.

The sensors are fully encapsulated to ensure complete protection from all but the very harshest of environments.

Click here to visit our main Bolt-On Sensing page

Posted in Load Cells & Force Sensors, Product News, Weighing | No Comments »

Batch Weighing System Controlled Through Touchscreen Technology

July 5th, 2005

touchscreen-system-150x150Applied Measurements Ltd was asked to design a batch weighing system where the ingredients of each batch would constantly vary.  To weigh the batches into the barrels AML built a stainless steel weighing platform incorporating load cells to the specific size required by the customer.  As the barrels could be dropped on to the weighing platform, positive overload stops were included to protect the load cells.

The output signal from the weighing platform is fed into a digital display, which has two set point relays.  Connected to the digital there is also a touch screen display, this enables the operator to see the live reading, the batch reading, the total batches and a numeric keypad to input the individual batch size.  The touch screen controls the set point relays in the digital display.

Also built into the control panel were two further digital indicators connected to PT100 studded-platform-150x150temperature probes monitoring two mixing vessels.  The complete batch weighing system was set up to let the batching control proceed, however if one of the mixing vessels temperatures went out of range the relays of the digital indicators would cut the pumps to the main mixing vessel.  The operator at a glance can see his two temperature readings, his live weight on the platform and has full control of his batching.

The total flexibility of the touch screen technology means that AML could program the batch weighing system to suit the customer’s requirements, including showing the customer’s name and logo on screen.  The use of the touch screen technology enables AML to offer a very cost effective flexible process control system for a diverse range of applications.

Posted in Application Stories, Systems, Weighing | No Comments »

Special Annular Load Cell Measures Tensioning System Spring Force

June 1st, 2005

spring-tensioner-200x200The overall tension in the system is controlled by a spring mechanism against an idler wheel.  Some form of load measurement was required, but it had to fit into the existing system, which did not allow space for a standard off-the-shelf load cell.

Applied Measurements Ltd designed and manufactured a custom load cell based on the CCG load cell concept, but to exactly fit the existing mechanical dimensions.  It had to be annular to allow the tensioning system to fit through the centre and to be extremely low in height to replace an existing washer.

To complete the system each load cell was supplied calibrated with a digital indicator containing 4 changeover relays.  Each system operated from a 240Vac supply, giving the system operators a visual reference of the tension in the system, plus the relays controlled an early warning alarm system allowing preventative maintenance.

Posted in Application Stories, Customised Sensors, Load Cells & Force Sensors | No Comments »

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