Principles and guidelines for selecting casting methods

1.Priority is given to sand casting,mainly due to its lower cost,simpler consumption process,and shorter consumption cycle compared to other casting methods;When the wet type cannot meet the request,consider using clay sand surface dry sand type,dry sand type,or other sand types;The weight of castings cast with clay green sand can range from a few kilograms to tens of kilograms,while castings consumed with clay dry sand can weigh tens of tons.

2.The casting method should be in line with the consumption batch.Casting methods such as low-pressure casting,die-casting,and centrifugal casting are only suitable for mass consumption due to the high cost of equipment and molds.

3.The appearance method should be suitable for the factory conditions.For example,it is suitable for large machine tools,bed bodies,and other castings.Generally,the core assembly method is used,without manufacturing appearance and sand boxes,and the core is assembled in the pit;And another factory adopts the sandbox appearance method to manufacture appearance;Different enterprises have different consumption conditions(including equipment,venue,employee quality,etc.),consumption habits,and accumulated experiences.Based on these conditions,it is necessary to consider what products are suitable and what products are not suitable(or cannot be).

4.To coordinate the precision requirements and cost of castings,the quality of machine tool castings mainly includes appearance quality,internal quality,and application quality.

Principles for pouring machine tool castings:

1.Machine tool casting clearing.The essence of machine tool casting cleaning is to beautify the casting,and the so-called cleaning is to improve the surface quality of the casting.

Regarding small items,first stop rough cleaning with a hexagonal drum,then use a shot blasting cleaning turntable to dispose of them for secondary precision,and then use a grinder with built-in dust removal equipment for finishing.After passing the inspection,apply anti rust paint and store them in the warehouse.For medium and large items,first use a vibrating sand blasting machine to apply large sand pellets,then send them to the shot blasting and clearing room for shot blasting and clearing.Then,manually use a handheld sand blasting machine for finishing,and apply anti rust paint to qualified products before storing them in the warehouse.

2.The quality of molten iron during melting and pouring on cast iron platforms has two main impacts on the surface quality of castings:firstly,the content of impurities in the molten iron,especially the content of iron oxide,which can easily produce slag inclusions or slag pores on the surface of castings;The second is the gas content in the molten iron,which is high and can easily cause porosity on the surface or under the skin of the casting.The main measures we have taken are to improve the temperature of the molten iron,establish a sound cupola detection system,and ensure that the cupola is in normal condition.

3."High temperature standing and low temperature pouring"is the control principle of pouring to reduce the porosity,shrinkage,and surface sand sticking defects of castings.Improve the level of casting technology and improve the surface quality of exported machine tool castings

4.Reasonably affirm and minimize the number of parting surfaces,in order to reduce casting surface defects such as burrs and uneven surfaces caused by parting surfaces;Improve the integrity of clay cores,reduce the number of joints between clay cores,and reduce the fit gaps between clay cores or between clay cores and molds,in order to improve the surface roughness and contour clarity of large castings.

5.The selection of process parameters has a significant impact on the dimensional accuracy and contour clarity of castings.After multiple process experiments,each process parameter was carefully selected.

6.The widely used casting technology results in improving the degree of casting technology to reduce casting defects,especially surface defects of machine tool castings.