Quality problems that can be produced by base materials and laminates

It is impossible to make any number of printed circuit boards without meeting some problems, some of which are due to the copper clad laminate material. In the actual manufacturing process of quality problems, often because the substrate material become the cause of the problem. Even a laminate technical specification that has been carefully written and has been practically implemented does not specify the test items that must be carried out to determine the reason why laminate is the cause of production process problems.


Surface problem

The phenomenon of signs: ink adhesion, coating adhesion is poor, some can not be etched away, and some can not solder.

Can be used to the inspection method: usually can see the water water formed in the plate surface for visual inspection or inspection using ultraviolet light irradiation, ultraviolet lamp radiation can be found in the copper foil copper foil is resin.

Possible causes:

1. because of the very dense and smooth surface caused by the mold film, the surface of the copper is too bright.

2. usually on the copper-clad side of the laminate, the laminate manufacturer does not remove the mold release agent.

3. copper foil pinhole, causing resin outflow, and deposited on the surface of the copper foil, which is usually seen in more than 3/4 ounce weight specifications thin copper foil, or environmental problems caused by the resin powder on the surface of copper foil laminated.

Terms of settlement:

1. laminate manufacturers use fabric like films or other release materials.

2. contact with laminate manufacturer, using mechanical or chemical methods of elimination.

3. contact with laminate manufacturer to check unqualified copper foil; obtain the removal of resin recommended solution to improve the manufacturing environment.

4. way to laminate manufacturers to get rid of the method. Regular use of hydrochloric acid is recommended, followed by mechanical removal.

5. before laminate manufacturing, before any change, cooperate with the laminate manufacturer, and specify the user's test items.

6. the staff of all educational processes wear gloves and take copper clad plates.  Find out whether indeed laminate in transit have the right pad of paper or loaded into the bag, and a pad of paper bags with low sulfur content, no dirt, no one is sure to use silicone containing detergent to contact copper foil, ensure the equipment in good condition.

7. degreasing all laminates before plating or graphic transfer process.

Machining problems

Phenomenon sign: punching, cutting, drilling processing quality is inconsistent, the coating adhesion is poor or in the metal hole coating is uneven.

Inspection methods: inspection of incoming materials, testing of various key mechanical processing operations, and the laminated material after hole metallization process, routine analysis.

Terms of settlement:

1. contact the laminate manufacturer to establish the test of the critical machinability requirements. The die should not be used as a test, otherwise the wear and change of the die will affect the test result. In any machining performance change problem, only when the problem is simultaneous with the change of batch number, can the quality of laminate be doubted.

2. refer to instructions for the manufacture of various types of laminates. Contact with laminate manufacturers to clarify the specific drilling speed, feed, bit and punch temperature of each level laminate. Remember: each manufacturer uses a mixture of different resins and substrates, and the recommendations are different.

3. carefully preheat the laminate and be sure to find any overheating zone, such as the overheated zone under the heating lamp. The principle of "first in first out" should be followed when heating materials.

4. check with the laminate manufacturer to obtain the aging characteristics data of the material. Turnover inventory makes inventory usually a newly produced sheet.  Be sure to find out the possible overheating in warehouse storage.

All kinds of soldering problems

The phenomenon of cold welding or soldering signs: a blasting hole.

Inspection methods: before and after the dip dip holes are often found in the analysis, copper stress, in addition, the incoming inspection of raw materials.

Terms of settlement:

Try to eliminate copper stress. The expansion of a laminate in the Z axis or thickness direction is usually related to the material. It can cause the fracture of the metallized hole. Recommendations for laminate manufacturers to obtain materials with smaller Z axis expansion.

Excessive size change

The phenomenon of signs: in processing or post solder substrate size out of tolerance or not alignment.

Inspection method: the quality control is fully carried out during the processing.

Possible causes:

1. the direction of the texture and texture of the paper based material is not noticed, and the vertical expansion is about half of the horizontal direction. And the substrate can not be restored to its original size after cooling.

If the local stress in the 2. laminate is not released, it sometimes causes irregular dimensional changes in the process.

Terms of settlement:

1. ask all the workers to cut the plate according to the same structure and texture direction. If the dimension changes beyond the allowable range, the base material can be considered.

2. contact the laminate manufacturer to obtain recommendations on how to release the material stress prior to processing.


 

(Source: internal information)

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