What are the advantages and disadvantages of resin sand casting?

一. Resin sand has the following advantages:

 1. The casting has high dimensional accuracy, clear outline, smooth surface, good appearance quality, dense structure and high comprehensive quality of casting.
This is because resin sand molding can eliminate many factors that deform the mold (core).
E.g:
(1) The molding sand has good fluidity and does not need to be compacted by a tamping machine, which reduces the damage and deformation of the pattern (core box);
(2) After the sand mold (core) is cured, the mold is removed, which reduces the deformation caused by the loose pattern before the mold and the damage of the sand mold (core) when the mold is removed;
(3) No need to repair, reducing the deformation caused by repairing;
(4) No need to bake, reducing the deformation of the mold (core) caused by baking;
(5) The strength of the mold is high and the surface stability is good, so the gap between the core head is small and the negative number of the parting is small, which reduces the damage and deformation of the mold in the process of core setting and mold matching, and ensures the mold matching accuracy;
(6) The mold (core) has high hardness and good thermal stability, which can effectively resist the wall retreat and migration during pouring, and reduce the thermal shock deformation of the mold (such as sand expansion, etc.);
(7) The collapsibility of the molding sand is good, and the cleaning and grinding are easy, thereby reducing the damage to the shape accuracy of the casting in the process of sand removal and shovel trimming.
To sum up, since the factors affecting the deformation and damage of the mold and castings are eliminated to the greatest extent in each process, the surface quality of the resin sand castings and the geometric accuracy of the castings can be improved 1—1— Grade 2, reaching CT7-9 grade accuracy and 1-2mm / 600mm straightness, the surface roughness is more improved.

     2 . The molding efficiency is high, the productivity and site utilization rate are improved, and the production cycle is shortened. This is because:
(1) The molding sand has good fluidity and does not need to be compacted by a tamping machine, which saves a lot of tamping workload and greatly simplifies the molding operation;
 (2) The strength of the mold is high, which saves the workload of repairing after the mold is removed;
(3) After the alcohol-based paint on the type (core) is spot-dried, the drying process can be omitted, which saves time and space;
 (4) Dry mechanical regeneration after the old sand is recovered, so that the sand treatment is a closed system, which is convenient for mechanization, and can save a lot of auxiliary labor such as old sand treatment, molding sand mixing and transportation;
(5) The collapsibility of the molding sand is good, the sand falling is easy, and the dressing workload is small.
(6) Save some preparation work before modeling (core). Such as ferrule solid and so on.
According to general statistics, the production efficiency can be increased by 40-100% and the output per unit molding area can be increased by 20-50% after replacing the clay baking sand with fat sand.
 3. Reduce labor intensity, greatly improve labor conditions and working environment, especially reduce noise, silica dust, etc., and reduce environmental pollution.
 4. Energy saving. This is manifested in the cancellation of drying kiln and hydraulic sand cleaning, improving the yield of molten iron, and greatly reducing the consumption of compressed air, so as to save water, electricity, coal (coke) and so on.
5. Resin sand mold (core) has high strength (including high temperature strength), good formability, lower gas generation than other organic molds, good thermal stability, and good air permeability, which can greatly reduce the sticking sand, sand inclusion, blisters and pores of the casting. , shrinkage cavities, cracks and other casting defects, thereby reducing the scrap rate, and can manufacture complex and key parts that are difficult to make with clay sand.
6. It is easy to recycle old sand, and it can reach 90-95% recycling rate. It has remarkable effects in saving new sand, reducing transportation, and preventing waste pollution.

 二. The self-hardening furan mold has some shortcomings, and corresponding countermeasures should be taken.

 1 . Higher requirements for raw sand, such as particle size, particle shape, SI0 2 content, micropowder content, alkali metal salt and clay content, etc. have strict requirements;
 2 . Air temperature and humidity have great influence on hardening speed and strength after curing;
 3. Compared with the casting mold with inorganic binder, the resin sand has higher gas generation, and if the measures are improper, it is easy to produce porosity defects.
4. Since the hardening mechanism is dehydration condensation type, the hardening reaction takes a certain time, the turnover rate of the pattern is low, and it is not easy to adapt to the production of large-scale castings;
5. Compared with clay sand, the cost is still higher;
6. For castings such as ductile iron or low-C stainless steel, the surface may cause poor spheroidization or carburization due to sulphurization or carburization, and defects such as cracks are prone to occur on thin-walled and complex steel castings;

7. There are irritating odors and some harmful gases during pouring, and the amount of CO gas is large, so good ventilation conditions are required.

Qingdao  Bestech Machinery Co.,Ltd ,  specializes in the production of  foundry machinery ( Green Sand Molding and pocessing line,  Automtatic horizontal and veritcal flaskless molding machine, hydraulic multiple pistons sand molding machine, resin sand processing line,  sand mixer machine , ) Shot blasting machines,dust collector. Warmly welcome guests to visit our factory.