Furnaces ensure high quality for ceramic sheet
Leading manufacturer of thermisters, has increased its production facilities with the addition of a fourth top-hat furnace for processing ceramic sheet at up to 1300 deg C.
GE Infrastructure Sensing, a leading manufacturer of thermisters, has increased its production facilities with the addition of a fourth Carbolite top-hat furnace for processing ceramic sheet at temperatures up to 1300 deg C. The thermal sensors manufactured by the company, which are widely used in the automotive industry and in heating, ventilation and refrigeration equipment, incorporate several types of ceramics to suit different applications. The materials are produced from metal oxides mixed with binders which are formed into thin sheets and then fired in the Carbolite furnaces.
Heating the sheets to 400 deg C over four hours burns off the polymer binders, after which the material is sintered at between 1200 deg C and 1300 deg C to form the new crystal structure.
Sintering can last up to 20 hours, depending on the formulation and the performance characteristics required.
After cooling, the sheets are cut with a diamond saw to the size required for the finished assembly.
The hearth, which can hold many sheets at a time, runs on a track and is driven by an electric motor, so it can be moved in and out of the furnace.
The heating elements are in a ‘top hat’ structure, which is lowered over the hearth when a charge is being processed and raised at the end of a cycle.
The success of the sintering process depends on heating the material to very accurate and uniform temperatures, so the furnaces have been designed to provide a working area within the chamber 200mm wide x 600mm long x 350mm high where temperature uniformity is 12 deg C at 1200 deg C.
Access ports allow thermocouples to monitor load temperatures in the chamber
Upgrade raises ceramics processing precision
Ceramics producer has recently upgraded its vacuum brazing facility at their Rugby factory with state of the art HMI to provide high precision in temperature and vacuum levels.
Faced with new product challenges, Engineering Manager Martin Davidson and Development Engineer Tariq Zaman took a critical look at their 1980s Wentgate design vacuum furnace. They concluded that it was still in very good order and in principle suitable for the next generation of ceramic to metal brazing applications. However the temperature and vacuum profiles would require modification and the furnace was running with an early Eurotherm temperature controller.
Personnel with relevant experience of this unit were no longer available.
Morgan found they might have to relearn the programming routine themselves, but instead called on the services of control engineers Specnow to write and prove new profiles.
Process cycles employed in ceramic brazing are often critical, calling for a high degree of precision in temperature and vacuum levels.
On tackling the problem Morgan and Specnow recognised that the existing controls lacked response and flexibility, presenting obstacles to success with the new parts.
Morgan was able to make the case for purchase of Specnow’s Microlink furnace control package - a Touch Screen SCADA type solution specially designed for Vacuum Furnaces.
Specnow stripped out the old instrumentation on site and installed the pre-configured Microlink in less than a week.
To minimise outage the work was carried out at the same time as a major furnace service.
Zaman explained, ‘We had been trying to modify our historical processes but the old unit proved very user unfriendly.
When we wanted to develop a brazing solution we had to carry out a complete run before we could evaluate.
The Microlink allows us to modify the cycle while in progress and see the result in the load temperature distribution and vacuum levels immediately at the touch screen.
It is an excellent tool for development; after optimising the process we can easily store as many programmes as necessary.
The day to day operators can access them later via their own passwords.’ Davidson observed a number of operational advantages, ‘We now have software control of the process with Microlink using the average of 4 or more job thermocouples.
This has enabled us to cut the usually long soak times at the critical braze temperature and gives us an extra run per day.
We have achieved faster turnaround and lower reject rates.
Another software feature gives us in-built vacuum leak detection and vacuum pump performance monitoring.
This helps us to maintain good vacuum conditions, essential to the success and quality of our production.
The user friendliness of the new system is also greatly appreciated: high visibility and ease of operation with the touch screen has given us greater understanding and confidence in the process.
Specnow left us completely self sufficient, able to programme, maintain and troubleshoot the entire furnace.
Our operators were fully trained in a matter of hours.’ In designing Microlink, Specnow used a standard PC and a quality PLC to replace conventional temperature controllers, chart recorders, meters and other redundant components.
For the heart of the system software, Specnow chose ‘DataManager’, a proprietary package that can communicate with a large range of instruments and PLCs including Allen Bradley, Mitsubishi, Omron and Siemens.
With the reduced component count there is an increase in machine reliability and focus.
The operator has only one system to address and interpret, and quickly becomes proficient.
A chart screen shows changes to the program and the operator can zoom in and out of the display.
The solution obviates the need for paper rolls.
The chart can be printed at any time or exported as a csv file to be opened in Excel as part of a report.
Microlink has been supplied with new furnaces and retrofitted as an upgrade in many parts of Europe.
The units are available with options including hot zone uniformity, thermocouple, and vacuum sensor calibration.
Specnow has developed a library of friendly screens that are readily adapted to the precise needs of the customer.
Modem link and emergency support are available with contract maintenance.
Furnaces help research barrier coatings
A specially designed thermal cycling rig and seven chamber furnaces are to expand facilities for research and development work on thermal barrier coatings for turbomachinery.
A specially designed thermal cycling rig (TCR) and seven chamber furnaces have been supplied by Carbolite to the Siemens Industrial Turbomachinery factory at Lincoln to expand facilities for research and development work on thermal barrier coatings. The Lincoln factory manufactures small industrial gas turbines for power generation and mechanical drive applications with outputs from 3mW to 13mW. The Carbolite equipment is being used to evaluate coating materials such as yttria-stabilised zirconia (YSZ) bonded to cast and wrought nickel-based super-alloys used in the production of hot gas path components.
While the chamber furnaces provide isothermal exposure for this work, enabling samples to be heated to a temperature, held and then cooled, the TCR allows samples to be subjected to long cycles of heating and cooling that accurately simulate thermal conditions within a turbine.
The equipment has a maximum operating temperature of 1500 deg C, but the maximum temperatures used by Siemens are generally between 1000 deg C and 1300 deg C.
In future the company may also use the equipment for thermal fatigue testing.
The TCR consists of a heating zone above a loading and quench zone, with an actuator that raises and lowers samples between the two.
In a typical long-term test a sample is lifted into the heating zone, heated to a pre-set temperature, held at that temperature and then lowered into the quench area where it is air-cooled before being raised again into the heating zone for another cycle.
Time and temperature are controlled through a cascade system, with over-temperature protection provided for the heating chamber.
A probe thermocouple in the centre of the lifting rod provides temperature readings for the control system and is also linked to a six-channel digital-display chart recorder.
The heating elements used have been designed to increase resistance to oxidisation and to provide easy replacement when required.
Rebuilds raise vacuum furnace performance
Aerospace contractors and advanced materials and device suppliers now view quality used plant - such as vacuum furnaces -as a highly respectable option.
The market for used vacuum furnaces has been gaining ground in recent years due in part to the visibility provided by the web. Many buyers including aerospace contractors and advanced materials and device suppliers now view quality used plant as a highly respectable option. Increasingly active in this area, Specnow undertakes major overhauls on site and supplies quality rebuilds as well as new furnaces customised for the application.
Specnow has recently obtained a stock of used Wentgate design vacuum furnaces with 20 or 30 litre capacities.
The systems have stainless steel chambers set in their original frames.
Well maintained by their previous owners, all of the hardware is in good order.
Ideally suited to the high tech environment, these furnaces will be re-engineered and offered for sale with installation, training and guarantee at typically 50% of new market prices.
When carrying out rebuilds the entire system is stripped and refurbished, replacing any obsolete electrical and mechanical components.
Refurbishment can provide an optimum solution for many customers.
Specnow maintains that it is possible to enhance the capability of the original furnace very significantly using Touch Screen computer technology.
Configured as a Human Machine Interface, Specnow’s Microllink displays the maintenance condition of the furnace, vacuum pumps, hot zone uniformity, and calibration.
As well as improving thermal process control, modern electronics add operational supervision and reporting facilities (for procedures like NADCAP), networking, and modem service support.
The system renders chart recorders and vacuum gauges redundant.
Many other components are eliminated, leading to improved reliability while cost is reduced.
Furnace rebuild projects were recently completed for UK customers Morgan Advanced Ceramics and Cathodeon who carry out a range of vacuum brazing and heat treatment processes on ceramic, glass and metal combinations.
Infra-red speeds moulding with less maintenance
Installing a carbon infra-red system to pre-heat acoustic soundproofing sheets prior to moulding has significantly reduced production cycle times and virtually eliminated maintenance costs.
By installing a carbon infra-red system to pre-heat acoustic soundproofing sheets prior to moulding, Faurecia has significantly reduced production cycle times and virtually eliminated maintenance costs and machine down-time on one of its major moulding machines. Faurecia is a world leader in the supply of automotive equipment and its Washington, Tyne and Wear, plant produces acoustic products for vehicle interiors and luggage compartments. Essentially, many of these products are produced by moulding a thick sheet of PE-EVA (polyethylene ethylene vinyl acetate) to the required shape and then applying a layer of polyurethane foam to impart the sound-deadening properties.
An essential part of the moulding process is the pre-heating of the PE-EVA sheet.
Some of the moulding machines at Faurecia apply this preheat before the sheet is dropped into the mould for forming and one such machine has recently up-graded its pre-heat system to incorporate Heraeus medium wave emitters.
However, one of the moulding machines at the Washington factory, relies on heating the PE-EVA blank while it is actually in the mould.
This heat was previously delivered by medium wave infra-red foil heaters, which were proving expensive to maintain.
Moreover, the slowness of the heating operation, which also involved pre-heating the blanks with large hot water radiators, was starting to create a production bottleneck.
In an effort to rectify this situation, Faurecia contacted infra-red specialists Heraeus Noblelight, who investigated the possibilities of retrofitting a more modern, more efficient infra-red system to meet the current requirements of the moulding machine.
Initial on-site trials immediately established that carbon infra-red emitters could eliminate the need for pre-heating, as they provided a 16% increase in heat-up rates.
Consequently, it was possible to dispense with the hot water radiators and associated stands and create valuable new floor space.
It also proved possible to retrofit the new carbon infra-red system using many of the existing electrical supply connections of the old system, as well as the existing control panel and pyrometer.
In operation, the blank sheets are now heated in the mould, without any pre-heat, by means of a 104kW carbon medium wave cassette, which carries 26, 4kW twin tube emitters, arranged in 13 zones.
The emitters are switched on when the sheet is dropped into the mould and switched off by the pyrometer, on achieving a pre-set temperature.
Switch on/switch off times are less than one second.
Since installation, it has been found that cycle times have been reduced by 20 seconds and there are energy savings of 9kW/hour because of the elimination of the pre-heating alone.
Furthermore, maintenance costs and duties have been cut dramatically, as the twin tube emitters are proving much more durable than the original foil heaters and any infrequent change-over involves minimum downtime.
Heraeus Noblelight, part of the multi-national Heraeus Group, specialises in the production and application of high quality energy sources covering the entire electromagnetic spectrum, from ultra-violet to infra-red.
It has over 40 years experience in infra-red technology and offers the expertise, products and systems to provide efficient and effective solutions to drying, heating and curing problems throughout industry.
Air knife systems have many functions
Airknife systems are ideal for drying, cooling, curing, cleaning and even deionisation of web materials and can even be employed for spreading and distributing coatings for enrobing processes.
Airknife systems are ideal for drying, cooling, curing, cleaning and even deionisation of web materials and can even be employed for spreading and distributing coatings for enrobing processes. Providing a continuous and even curtain of air across full web widths via linear plenums, they ensure the full surface area is treated. Blower driven Airknife systems, such as manufactured by Air Control Systems (ACI) of Chard, UK, provide a cleaner, quieter and more cost-efficient option than conventional compressed air alternatives.
They are cleaner because there is no risk of air contamination from oil and/or condensate; quieter because they deliver large volumes of air at high velocity as opposed to low volumes at high pressure; and more cost effective because they use correctly sized dedicated blowers that require only minimal maintenance and do not suffer from the innate weaknesses of compressed air systems (leakages, airflow impedance through extended airlines and compressor sizing to match maximum line loadings).
For applications that experience static problems, a specially developed de-ionisation bar can be added.
This generates an electrical field that causes air molecules to separate into positive and negative ions that are propelled into the target field where they neutralise any static charge on the web.
ACI Airknife systems may be as simple as connecting a single blower to a 1m Airknife, or it might incorporate multiple blowers and airknives, as well as including an array of accessories, depending on the size and shape of the customer’s product.
The blower might be located locally or remotely and housed in an acoustic chamber.
Furnaces monitored and controlled remotely
Updating of a Dutch heat treatment furnace includes program controllers for the wireless control of heating devices and systems for total process control.
Furnaces monitored and controlled remotely Updating of a Dutch heat treatment furnace includes program controllers for the wireless control of heating devices and systems for total process control. Recently, Heatmasters completely renewed a heat treatment furnace for Siemens Demag Delaval in Hengelo, The Netherlands. The control system consists of a HM2000 heat treatment control software and HM Rige/26 program controllers for the wireless control of heating devices.
The systems control the entire process from preparing heat treatment instructions to maintaining records and storing results.
When Heatmasters HM-Rige/26 controllers are equipped with HM-IceStar control cards, they enable worldwide alarm and monitoring of heat treatment processes because the control card includes an alarm board and a GSM modem.
The distance between the process supervisor and the heating unit is unlimited and can be used to enable alarm messages and process data, in the form of a SMS message, to be passed directly to a mobile phone.
The HM-IceStar alarm system with a monitoring facility also makes it possible to carry out long distance programming, and request the status of process parameters at any time with a GSM-phone.
The system has many options: for example, in an emergency, the operator can send a SMS message, or even make phone calls from the heating unit.
At Hengelo, the control system is equipped with a GSM-alarm system to provide safe and secure heat treatment processes.
Heat treating large vessels and castings - Heatmasters has also helped the Antritz Power Company with the on-site treatment of large vessels.
When Antritz produced a process vessel measuring 4m diameter x 80m for the Fortum refinery in Finland, Heatmaster’s service company carried out the heat treatment.
The vessel was treated in two parts and the joint weld was treated on-site.
In 2004, the World Economic Forum ranked Finland as the most competitive country in the world - ahead of the USA, all other Nordic countries, Japan and Great Britain.
Heatmasters, located in Lahti, Finland, are heat treatment specialists who have harnessed the advantages of computer-, information- and GSM technologies to enable their new generation of controllers, heat treatment software and program controllers to provide long-distance process monitoring from one country to another.
Data transfer includes worldwide alarm systems, fast calibration and simple document creation and transfer, as well as the computer storage of heat treatment programs and results.
The company uses stationary and mobile furnaces to carry out heat treatment projects in over 20 countries.
Heat treated fasteners blackened attractively
All types of heat-treated fasteners and other bulk-handled parts can be blackened in bulk with non-polluting black oxide - a process that is fast and economical.
Now there is a better in-house method for finishing heat treated fasteners to achieve an attractive and protective black oxide surface. The Tru Temp system produces a high quality, non-dimensional black finish - directly over light heat treat scale - on all types of fasteners and other bulk-handled parts. Since the Tru Temp process operates at only 200 deg F, it avoids the severe splattering and boilover hazards often seen with conventional hot oxide tanks.
The relatively mild solutions used in the process line also prevent the formation of red coatings and white salt leaching that often plague ordinary black oxide finishes.
Small parts are best handled in a rotating process barrel for greatest economy.
When rotated at 1-2 rev/min, these barrel systems efficiently blacken the parts without scuffing the edges.
Compared to other finishing methods, the Tru Temp process is fast and economical - processing time is only about 25 minutes and typical chemical cost is about $.01 per pound of finished parts.
Because the Tru Temp process contains no EPA regulated chemicals, there is usually no need for waste treatment equipment.
In most sewer districts the rinse waters are considered sewerable as non-hazardous effluent.
This feature simplifies the installation and minimises the capital investment needed to set up the process line.
The Tru Temp process is an effective blackening tool for all types of bulk handled parts, such as threaded fasteners, screw machine parts, stampings, forgings and even MIM parts.
Many larger pieces can also be successfully bulk processed, in stationary baskets, as long as they can be stacked to drain well and avoid flat-against-flat part contact.
The Tru Temp process is ideal for all dimensionally critical parts and meets military specification MIL-DTL-13924 Class 1, and AMS 2485.
The process also makes ISO compliance easier by keeping the finishing process in-house where part quality and inventory control is better managed.
Guide educates on electric thermal systems
Thermal Component Application Guide is designed to assists engineers in understanding the principles of electric thermal systems and components as they apply to various heating tasks.
Watlow are pleased to announce the publication of the Thermal Component Application Guide for engineers. The guide is designed to assists engineers in understanding the principles of electric thermal systems and components as they apply to various heating tasks. Its purpose is to give you theory, general calculations and engineering data along with examples for solving heating problems.
The guide is organised into sections dealing with the basic facets of an electric thermal system: * Electric Heaters - includes heater product overview, power calculations, applications and selection factors.
* Temperature Sensors - includes sensor product overview, sensor types and comparisons, RTD and Thermistor application guides, sensor placement and reference tables.
* Temperature Controllers - includes control product overview, thermal control principles, control output comparisons and data communications guide.
* Power Controllers - includes power switching overview, SCR theory and firing methods, extending heater life and SCR protection.
* Wiring Practices - includes helpful wiring guidelines, reduction of electrical noise, practical tips and special considerations.
* Reference Data - includes conversion factors, physical properties of solids, liquids and gases, corrosion guide and fully worked examples of industrial heating applications.
The guide is based on 80 years of experience where Watlow have designed over one million different thermal system packages.
Plasma systems producer sets up in USA
Diener Electronic, supplier of atmospheric and low pressure plasma systems, has established its North American headquarters - Diener Electronic North America - based in Reading, Pennsylvania.
Diener Electronic +Co KG, a leading supplier of atmospheric and low pressure plasma systems, has announced its expansion into North America with the establishment of its North American headquarters - Diener Electronic North America, based in Reading, Pennsylvania. Industry veteran Dennis Merkel has been named vice president, Marketing and Sales of Diener Electronic North America. Diener Electronic is a major supplier and manufacturer of plasma cleaning and etching equipment around the world.
The company has set its sights on being a complete provider of ‘cutting-edge’ plasma solutions in a global market.
Diener Electronic President Christof Diener managing director said, ‘This is the beginning of several strategic moves’.
‘We have focused our business on a few key applications, with a range of highly innovative products that meet the needs of our targeted customer base’.
‘Now we can provide the level of customer service our customers will need during the evaluation, development and installation of our products into their critical manufacturing process.’ Diener added: ‘Since 1993, our years of research in plasma surface technology has brought us to the forefront of this technology and warrants our participation in the global semiconductor, plastics, and medical industries’.
‘I am excited to have Dennis join us’.
‘He has an exceptional track record for growing sales and profitability and he has a strong command of the markets we are focusing on.’ Merkel said: ‘By forming Diener Electronic North America, we are able to give the US market a direct connection to our plasma technology and complete range of plasma cleaning, activation, etching, and polymerisation products’.
‘Our North American headquarters will also be a Manufacturing Development and Demonstration Center’.
‘We will have a lot of equipment that customers will be able to fully familiarise themselves with before buying’.
‘We also offer free processing of customer samples to prove the effectiveness of plasma surface technology’.
‘This is a major step for Diener in their continuing globalisation programme.’ Merkel has a very successful international track record; including his recent accomplishments significantly growing sales each year during his three years as Marketing Director for SiliconCert.
Prior to joining SiliconCert, Merkel had responsibility for the Asia/Pacific region as Global Account manager at Kulicke and Soffa Industries.
* About Diener Electronic - Diener Electronic is a leader in the research and development of atmospheric and low pressure plasma systems which are utilized in several applications including the electronics, plastics, and medical industries.
The plasma technology is used for several types of surface treatments.
Some of the applications are for cleaning contaminated devices, plasma activation of plastic parts, etching of PTFE, etching of silicon and coating of layers similar to PTFE.
Plasma technology is used for various applications, where materials have to be combined or where surfaces need special modification.
In the electronic industry the machines are typically used for cleaning surfaces prior to wire bonding or die bonding, or for etching of silicon wafers.
In the plastics industry the machines are used for surface activation of the plastic materials so that they can be bonded together effectively.
Plasma machines may also be used to deposit polymer layers onto a substrate to make it scratchproof.
Medical applications are primarily for plastics activation.
Various different process gases are used in the chambers for these different functions.
Diener Electronic +Co KG is a privately held company based in Nagold, Germany.