Technical Library | 2019-11-12 02:09:22.0
Thermal shock test chamber can be used for testing the chemical change or physical damage on composite materials caused by the thermal expansion and contraction of the sample in the shortest time,which is subjected to extremely and continuous high and low temperature environment.so how to check the temperature recovery time of this chamber? Normally we take following steps to inspect the temepratuire recovering time: 1.Install the temperature sensor at the specified position, and adjust the temperature controller of hot zone and cold zone to the required nominal temperature respectively. 2.The temperature increases and reduces respectively,30min after temperature in two zones reach stable status,record temperature value of the measuring point,pls set the temperature value of two zones to be required nominal temperature. 3.The temperature shock test chamber automatically places the inspected load into theh ot zone,select the corresponding retention time according to regulated standard. 4.Set the transfer time,then the inspection load is transferred from hot zone to cold zone, and the temperature of the measuring point is observed and recorded, and then the reverse conversion of the load from cold zone to hot zone is carried out according to the same method, and the temperature of the measuring point is observed and recorded. www.climatechambers.com
Technical Library | 2024-04-29 21:39:52.0
In this paper, we develop and put into practice an Automatic Optical Inspection (AOI) system based on machine vision to check the holes on a printed circuit board (PCB). We incorporate the hardware and software. For the hardware part, we combine a PC, the three-axis positioning system, a lighting device and CCD cameras. For the software part, we utilize image registration, image segmentation, drill numbering, drill contrast, and defect displays to achieve this system. Results indicated that an accuracy of 5µm could be achieved in errors of the PCB holes allowing comparisons to be made. This is significant in inspecting the missing, the multi-hole and the incorrect location of the holes. However, previous work only focusses on one or other feature of the holes. Our research is able to assess multiple features: missing holes, incorrectly located holes and excessive holes. Equally, our results could be displayed as a bar chart and target plot. This has not been achieved before. These displays help users analyze the causes of errors and immediately correct the problems. Additionally, this AOI system is valuable for checking a large number of holes and finding out the defective ones on a PCB. Meanwhile, we apply a 0.1mm image resolution which is better than others used in industry. We set a detecting standard based on 2mm diameter of circles to diagnose the quality of the holes within 10 seconds.
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