PCBA Test Fixture

 

PCBA testing is a very important step in the whole electronic manufacturing service. It can strictly control the delivery quality in the final stage. It can find out the problems in time so as to adjust the previous process such as SMT and DIP, optimize the process flow, and realize the quality control layer by layer with a testing chain.

 

1. PCBA Test Classification

1.1 ICT test

It mainly includes circuit on/off, voltage and current value, fluctuation curve, amplitude, noise, etc.

1.2 FCT test

It need to program to the IC and do the function test to the whole PCBA board. To find out the problems in the hardware and software, and equip the necessary production fixture and test frame.

1.3 The fatigue test

To select some PCBA boards at random and perform high-frequency and long-term operations on the functions to check whether faults occur. Through the test, judge the probability of failure, feedback the performance of PCBA board in electronic products.

1.4 Environmental test

To expose PCBA boards  to the limits of temperature, humidity, drop, splash and vibration to obtain the test results of random samples. In this way, to infer the reliability of the entire PCBA board batch.

  • Aging test

The aging test is mainly to electrify the PCBA board and electronic products for a long time to keep them working and observe whether any failure occurs.

The below picture is our aging test room. Our technicians are doing the aging test for one of the PCBA project we produced.

2. What is PCBA Test Fixture?

PCBA test fixture is to test and test the function, power calibration, life and performance of the product. Because it is mainly used in the PCBA production line for the test of various indicators of the product, so we call it PCBA test fixture.

 

3. Why we need Test Fixture?

Some PCBA boards we produced are used in smart cloth,smart home system, the small and medium sized equipment etc.

If we need to perform functional tests on such PCBA, the customer can send us the equipment, and we can complete the test steps only by installing the PCBA board on the equipment.

But some projects are for large equipment, such as laser cutting machines, car console, truck tracking equipment and so on. The customer cannot ship such large equipment to us, and some PCBA test points and voltage connections are complicated. In the sample test phase, we can solder some wires to the PCBA board for testing.

However, in the case of mass production test, that way is not convenient. When testing a PCBA function, we need insert many wiring harnesses, which will use a lot of time. Besides, it has a risk of error for the operator. It is easy to create artificial defects due to improper operation.The testing fixture can effectively avoid this kind of risk. At the same time, through the probe contact the PCB pads, it saves a lot of time to plug and pull the wire and connector. That can greatly improving the production efficiency. The test fixture makes our test easier and more convenient to operate.

4. How to produce a PCBA Test Fixture?

When testing PCBA board, it is generally necessary to customize special test fixture for PCBA board. So how can we make the test fixture suitable for this project? First of all, as a PCBA manufacturer, we need to provide Gerber files and PCBA photos to the test fixture factory. Then, our engineer will inform the requirements for special treatment to the test fixture factory. Next, the test fixture manufacturer designs the test fixture according to all the production files. Before making a fixture, we send an assembled PCBA board to fixture manufacturer, so that they can produce a fixture that fits the project better.

 

5. The principles of the test fixture

After making PCBA test fixture, just put the PCBA board into the test fixture to realize the positioning of PCBA board and test fixture. The accuracy of positioning has a great relationship with the manufacturing process of test fixture.

  • Fixture pressure plate or load plate in the design of the position must be accurate. We can not let the PCBA board crushed in the test.
  • Test fixture positioning should be accurate, connector docking smoothly.
  • The test fixture will have a certain design of a box, the test PCBA placed in the box, in the fixture design must maintain sufficient space box, box layout must be reasonable.
  • Test fixture reserved interface position should be correct, enough, convenient for operation.
  • The lock box of the fixture should be buckled or pressed to facilitate parts replacement and maintenance.
  • When the fixture is broken and aging, the needle can be changed for maintenance and continued use. If the fixture is damaged and cannot be repaired, it needs to be remade.

 

PCBA test fixtures are generally specially customized for a certain product, which can effectively improve productivity and shipment quality.