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Carbolite Keeps Hi-Tec Bikes at the Head of the Race
A specially designed electric furnace from Carbolite is being used by Hope Technology, based in Lancashire, to heat-treat brake discs for high-performance road and mountain bikes at rates up to 60 an hour and maximum temperatures of 1000°C in a continuous automatic process.
Since its formation 20 years ago Hope Technology has grown to become one of the UK’s leading manufacturers of high-performance cycle components, including disc brake systems, wheels, hubs, seat posts and lights. Equipment, which is often manufactured from stainless steel, titanium or aluminium, is used by leading competition riders and widely exported.
The company manufactures stainless-steel brake discs in 25 different standard designs and many bespoke designs to customers’ specifi cations. Diameters range from 140mm to 203mm, with a standard fi nished thickness of 1.8mm. The fi nished product must be within 0.01mm parallel in order to ensure consistent, smooth braking performance in extreme conditions. Previous use of pre-hardened sheet and induction heating on unhardened material had both failed to achieve the required specifi cation.
The discs are initially laser-cut from 2mm-thick stainless steel sheet, before the detailed machining is performed on a CNC milling centre. The discs are then linished to remove burrs before being heat-treated to harden them. To perform the hardening process, an actuator pushes one disc at a time from a stack of approximately 50 into the Carbolite slot-type furnace, which is held at a temperature between 950°C and 1000°C. Discs are heated for 60 to 90 seconds and then pushed into a water-cooled platen to fl atten and cool them. The entire process is automated and continuous, provided that the stack of unhardened discs is replenished.
The furnace temperature and the length of time each disc stays in the furnace are adjusted to suit the dimensions and amount of material involved. Control is provided by a high-precision PID unit linked to a thermocouple within the furnace chamber, with a separate temperature controller and thermocouple preventing over-temperature conditions.
Special Furnaces Simulate Aero-Engine Conditions
Laboratory & Industrial Furnaces & Ovens
Five specially designed Carbolite furnaces are enabling Meggitt Sensing Systems to perform long-term thermal test programmes that simulate conditions experienced by thermocouples in gas turbine aero-engines.
Meggitt Sensing Systems is part of Meggitt plc and one of the leading manufacturers of sensors for the aerospace sector. The furnaces were bought to enable the company to carry out research into the stability and accuracy of thermocouples as a result of long-term exposure to temperatures up to 1100°C in aero-engines. An important aspect of the equipment is the ability to simulate working conditions by cycling the thermocouples for long periods between typical operating temperatures and ambient temperatures.
In order to achieve this, the Carbolite furnaces have an automatic loading mechanism that push and pulls bundles of thermocouples in and out of the heating zone of a horizontal tube furnace. The fi ve furnaces built for Meggitt Sensing Systems have a maximum temperature of 1200°C and three heated zones in order to ensure precise temperature control at the centre of the 38mm diameter tube where the thermocouples are heated.
Each thermocouple is typically 2mm in diameter, and about 15 are usually tested at a time. Test programmes typically involve holding the samples in the furnace for 30 minutes at a temperature between 700°C and 1050°C, extracting them and exposing them to ambient air for fi ve minutes and then re-inserting them into the furnace again for 30 minutes. This sequence is generally repeated 4000 times before the samples are analysed and calibrated to determine the effects.
The furnace design allows entire cyclic programmes lasting over 2000 hours to be carried out automatically once the temperature and time data has been input into the control system. The fi ve furnaces allow Meggitt Sensing Systems to carry out several programmes in parallel at the same time.
The equipment has been designed to be compact and convenient to use in a laboratory situation, with double skin construction helping to keep the outer case cool and high-quality insulation optimising thermal effi ciency. A high-precision PID temperature controller, timer and associated power control equipment are housed within an integral control box.
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If you are looking for a complete line of furnaces & ovens, look no further than CARBOLITE.
n Temperature range from 20 °C to 3,000 °C
n Chamber, tube and application specific furnaces
n Customised solutions and modifications
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www.carbolite.com 17.07.2014 15:58:02
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