High Precision Machining is defined as a process of changing the dimensions or the performance of workpiece with machining facilities.
According to the temperature of the workpiece while in machining, high precision machining can be divided into cold working and hot working. Usually, machining under indoor temperature, and won't change cause chemical change or phisical phase change is named cold working. On the other hand, if under temperature, higher or lower than room temperature, which will lead to chemical changes or phase changes, it will be called as hot working.
For high precision machining, the machining tolerance can be up to 0.0001-0.001mm, the surface finish Ra can be 0.02-0.1um.
Machining precision is to describe the actual geometrical parameter of the part after machining, such as the size, the form, the position, comparing with the theoretical geometry parameter. The difference from these two parameters is the machining tolerance. The number of the difference show the machining accuracy, the bigger, the lower of the machining precision, the smaller, the higher machining precision.
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This instrument is suitable for testing the thermal insulation performance of flame-retardant protective clothing fabrics exposed to radiant heat sources and convection heat sources.
Second, the test method
Place a heat source on one side of the test sample and a copper calorimeter on the other side. Start the test and the sample clip is pushed into place. When the sensor value reaches the endurance limit of the second grade burn (the sensor temperature rises 35°C to 40°C), remove the sample clip from the heat source. From the intersection point of the response curve and the human tissue tolerance curve, the time for the second-degree burn was read to the nearest 0.1 second.
Third, the main technical indicators
1, using computer control, test results printout.
2, heat source heat flux: 50kw/m2 ~ 100kw/m2 adjustable.
3, heat source accuracy: ± 2%
4, calorimeter measurement range: 0 °C ~ 1600 °C ± 0.5 °C
5, the sample size: 150 × 150mm
6, power supply: AC220V50Hz4kW
Fourth, applicable standards
National standard GB8965.1-2009 "protective clothing flame retardant protection Part 1 flame retardant clothing"
ZF-622 overall protective tester Zhongbang
First, the main purpose