Cost analysis of building a material testing machine

Introduction:

The proposed structural design of a materials testing machine is presented in Fig 1. The testing machine is consisted of I-beams, bars, channels, grips, load cells, actuators and other necessary components. As a range of components are required for the materials testing machine, therefore, a primary cost analysis is very much needed to gather a rough idea about the final cost of the unit. This report discusses the cost analysis of a materials testing machine.

Identification of the Components and Materials:

I-beams: The bottom stands of the frame of the testing machine are made of I-beams. The material used for I- beams are steel alloys. Each of the I-beams is 400mm long, 254mm deep and 11.10mm thick.
Channels: Four channels of 254mm depth and 76mm flange are used to make the upper part of the frame. Each of the frames is 1500mm long and the materials are steel alloys. The ASTM specification of the channel is given in Table 1.
Angles and Rivets: Angels and Rivets are used for joining the channels, I-beams and actuators. Angles and rivets are made of steel alloys.
Steel Bars: Steel bars are needed to hold actuator C and the disk specimen. The steel bar which is used to hold the actuator C has 30mm length, 76mm width and 11.10 mm thickness. The steel bar which is used to hold the disk specimen has 40mm length, 100mm width and 11.10mm thickness.
Actuators: Actuators are supplied by RACO International (www.raco.de). Three actuators are needed for the testing machine and their positions are A, B and C in Fig 1. Actuator A is needed to be capable of providing a maximum of 500kN load. A RACO Electric Cylinder actuators Size 11 is the best fit for that place as it meets the requirements. Actuator B is needed to be capable of providing a maximum of 150kN load A RACO Electric Cylinder actuators Size 11 is the best fit for that place as it meets the requirements. Actuator C is needed to be capable of providing a maximum of 0.1kN of vibration moment. A RACO Electric Cylinder actuators Size 2 is the best fit for that place as it meets the requirements. Control units and mounting kits for the actuators are also supplied by RACO and included within individual price list.
Load Cells: Load cells for each actuator are bought from RACO International (www.raco.de). RACO load cells have class II strain gauge and can apply nominal thrust ±10kN (Tension/Compression). The output signal of RACO load cells are ±10 VDC for a very high accuracy level (0.2%). The input power needed is 19-28 VDC. Basically, load cells are integrated part of each of the actuators.
Heating Coil: Nickel-chrome heating coil is used as the heating unit to heat the tested blade. Nickel-chrome heating coil is capable of withstanding upto 1250°C. Custom Electric Manufacturing Limited (www.custom-electric.com) supplies the above mention heating coils.
Base: The base is a cast iron slab of 300mm, 250mm width and 250mm thickness.
Steel Grip: A steel grip is needed to hold the tested blade and transmit force into the blade from actuator C. The grip is made of steel alloy.
Identification of Manual Jobs/ Assembling:
Joining of all the components in the right fashion is the main manual job and that will take an extensive amount of time. However, in order to establish the testing machine jobs like drilling, riveting and welding are also needed.
Drilling: Drilling of the channels, I-beams and angles are pre-requisite to carry out riveting. It can be seen from Fig 1 that 64 (4 x 2 x 8) riveting are needed to interconnect the channels and another 32 (4 x 2 x 4) riveting are needed to join the I-beams and channels. Four riveting are needed to join Actuator B and the top channel. Two riveting is needed to join the steel bars and channel.
Screw and thread arrangements: The disc specimen is connected with the channels by tightly fashioned screw and thread arrangements. Both sides of the disc specimen are also connected with the steel bar and actuator A by means of screw and thread arrangements.
Temperature Sensor: A temperature Sensor is needed to measure the blade temperature during experiment. A High Performance 2-Colour Ratio Fibre Optic Infrared Temperature Measurement and Control System (model no IR2C-300-53-C4EI ) has been used as temperature Sensor and is capable of performing up to 3000°C. Omega.co.uk supplies the temperature sensor.

Cost Calculations:

Cost of manpower and build time:
Hiring of 2 skilled labours for 14 working hours @ £25/phpp equals to £700. This is the price for assembling of the components. The total building time is estimated to 28 work hour.
Running Costs:
Running costs are mainly maintenance costs. The DC cells are needed to be recharged and that may cost a maximum of £10 per test.
Samples which are subjected to test are very costly. For example, a specimen made of Nimonic 80A Superalloy weighing around 400gm are costing around £65.00 (source: www.goodfellow.com).
The heating coil became down with time and may last as high as 75-100 experiments. It will cost £350 to get replaced.

Minimization of the costs:

The costs can be minimised by using cheap actuators and sensors which are less accurate. For example, by sacrificing accuracy level to 2% from 0.02% will save £500-£1000 for each of the actuators. It is also possible to use a cheap temperature sensor which will be pricing around £500-£1000. But any costly equipment which will be replaced by a cheaper unit will cost in final accuracy of the results.

Conclusions:

This report estimates the building cost of a materials testing unit is approximately £14500 on the basis of current market prices of the components.