During the mixing process, the molding material is often too dry or too wet (also called too hard or too soft) due to factors such as changes in room temperature. Materials that are too dry or too wet are not conducive to molding, so adjustments must be made during production.

(1) Adjustment method for molding materials that are too wet

1. Liquid resin abrasive molding material:

(1) Switch to a higher viscosity liquid resin without changing the binder ratio.

(2) Add a certain proportion of filler (such as gypsum powder, mixed powder of calcium oxide and magnesium oxide) or dry materials according to the softness and hardness of the material.

(3) Place the overly wet molding material in a ventilated place to dry naturally for a period of time.

2. Powdered resin abrasive molding material:

(1) Switch to a higher viscosity liquid resin.

(2) Under the condition that the total binding dose remains unchanged, increase the amount of powdered resin and reduce the amount of liquid resin.

(3) Insert a certain amount of dry molding materials of the same specifications.

(2). Adjustment method for excessive drying of molding materials

1. Liquid resin abrasive molding material:

(1) Switch to a lower viscosity liquid resin without changing the binder ratio.

(2) Add an appropriate amount of solvent (such as alcohol) and mix evenly.

(3) Increase the mixing temperature.

2. Powdered resin abrasive molding material:

(1) Switch to a lower viscosity liquid resin.

(2) Add an appropriate amount of auxiliary wetting agent (such as furfural, engine oil, dibutyl phthalate, cresol, etc.).

(3) Under the condition that the total binding dose remains unchanged, increase the amount of liquid resin and reduce the amount of powdered resin.

Inspection of the uniformity of molding materials

1. Visual inspection method:

The color of the material is consistent, there is no binder clump, and the filler clump can be regarded as uniform. This method is simple but inaccurate.

Using the glass inspection method, spread the material between two glass plates and observe.

3. Solvent test method:

The uniformity of the molding material mixture can be evaluated by measuring certain physical and chemical properties of the molding material components.

The solvent test method is to measure the resin content of each part of the molding material to measure its uniformity.

Take a few grams of each material from different parts of the mixed pile, add 50~60ml of alcohol respectively, stir (to dissolve the resin), then filter out the alcohol with dissolved resin, and dry the residue at 105°C and weigh it. . The weight difference between the original sample and the remainder is the amount of resin in the sample. When the difference in resin content in each sample does not exceed 0.1% of the content, it means that the material has been mixed evenly. This method is more accurate, but takes longer.

Common waste products during the mixing process of molding materials

1. Inclusions - The molding material contains coarse particles or debris, which results in inclusion waste.

The main reason: caused by dirty equipment and tools and poor handling of raw materials.

Inclusions will cause: burns on the workpiece and damage to the surface finish of the workpiece.

2. Wrong ingredients

Main reason: Most of them are caused by carelessness (misreading the scale, failure to calibrate, etc.).

It will cause: inconsistent hardness, low strength, deformation and other waste products. Timely detection can lead to remediation.

3. Uneven mixing - visible lumps of auxiliary materials, dry abrasive balls, liquid resin spots on the surface of the body, and powdery resin deposition patterns are all examples of uneven mixing.

The main reasons are that the mixing time is short, the order of feeding is wrong, the viscosity of the resin liquid is high, and some parts of the mixing equipment are severely worn, etc.

Uneven mixing will result in uneven texture, uneven hardness, and stained faces. During grinding, the self-sharpening property is poor, the wear is uneven, the workpiece is easily burned, and the accuracy of the workpiece is affected.