Skill Requirements
1. Able to visually check whether the shape, color and other appearance of the product meet the requirements of the production task statement, can identify product surface defects, determine the type of surface defects and control the use, and can determine product defects such as pinholes, cracks, and poor curing.
2. Be able to use measuring tools such as meter rulers and vernier calipers to measure the size of the product and confirm whether it is within the error range.
3. Be able to inspect the quality of FRP pultrusion products, analyze the causes of defects such as burrs, bubbles, cracks, and uncured completeness, and propose solutions.
Relevant knowledge Apparent characteristics of pultruded products
Qualified pultruded products should have a smooth and flat surface, free of defects such as pores, cracks, bubbles, delamination, and whitening. But using different reinforcement materials, the appearance of pultruded products will also show different effects. The surface of pure fiberglass products should be the best, delicate and smooth to the touch. However, due to the consideration of transverse strength, most pultruded products will be covered with materials such as stitched felt and continuous felt on the surface. This surface is relatively rough due to the random arrangement of stitched lines or chopped fibers on the felt. In this case, a layer of surface felt can be added to the outermost layer. In addition to improving the appearance of the product, it can also reduce the friction between the pultruded product and the mold and improve the corrosion resistance of the product.
Knowledge of surface defects of pultruded products
The contents of pultruded product inspection mainly include: appearance inspection, integrity inspection and dimensional inspection. There are roughly three reasons for the defects of pultruded products: material composition, process parameters and process methods. Material composition refers to defects caused by quality factors such as resin formula, roving, glass fiber mat, surface felt; process parameters refer to defects caused by improper setting of mold temperature, pultrusion speed and other parameters; process method refers to resin impregnation method, preform mold , Defects associated with forming dies and pultrusion equipment.
Dimensional measuring instrument use
In pultruded products, the commonly used measuring instruments are as follows:
1. Box ruler is used to measure the length of pultruded products, the range is generally 3m, 5m, etc., and the accuracy is 1 mm.
2. The vernier caliper is used to detect the outline size of the product, such as thickness, width, etc., the measuring range is generally 250mm, and its accuracy is 0.02mm.
3. The wide sitting square is used to detect the perpendicularity between the cutting surface of the product and the length direction.
4. The square is used to check the deviation of the right angle inside and outside the product, marked with a scale, and can also be used for line drawing in post-processing.
5. The level is generally used when the mold is leveled to ensure the consistency between the mold and the traction table.
Quality inspection technology of pultruded products
There are many quality inspections for pultruded products, including appearance, dimensional accuracy, performance indicators and other aspects.
1. Appearance mainly refers to whether the color of the product is uniform, whether there are cracks on the surface and end face of the product, whether the surface is smooth, etc. Appearance is the most basic and direct inspection item for pultruded products, and visual inspection is generally used.
2. Dimensional accuracy mainly refers to whether the thickness and angle of each part of the cross-section of the product are within the tolerance range required by the customer. Generally, vernier calipers and squares are used to measure. Products with higher requirements will also strictly control the flatness and straightness of the product, which needs to be sent to a special testing agency for testing. If it is a large batch of production, it can also be specially made to measure the flatness and straightness. Straightness tooling is convenient for inspection at any time in daily production to ensure product quality.
3. Performance indicators There are many performance test items for pultruded products. Generally, standard samples are processed and tested according to national standards. There are special testing institutions.