Self-hardening resin sand casting process details explained(2)
4、The whole process of resin sand casting production shall be discussed
In order to standardize the production process of resin sand casting, strictly implement the operation process, reduce the scrap and reduce the production cost of castings due to the violation of the process or improper operation, the production operation process procedures are formulated. This procedure is applicable to the whole process of production of all resin sand castings in the company and all kinds of operators related to it. The following is an excerpt for your reference and reading.
4.1 Process regulations
(1) the technical requirements or specifications of the main raw materials
(2) Raw sand (natural quartz sand)
Grain size: 40/70 mesh (medium to large pieces) or 50/100 mesh (general pieces).
Chemical composition: SiO2 >90%, mud content <0.2%~0.3%, water content <0.1~0.2%.
Micron content (below 140 mesh sieve) ≤0.5~1.0%, acid consumption value <5ml, scorch amount <5, particle shape: round or polygonal.
(3) regenerated sand scorching amount <3.0%; acid consumption value <2.0ml; PH value <5; 200 mesh sieve sump <1%; sump amount <0.2%; water content <0.2%.
(4) Furan resin contains 2.0~5.0% nitrogen; 24h tensile strength>1.5MPa; free formaldehyde<0.3%; viscosity<60mPa.s; density1.15~1.25 g/cm3; free phenol<0.3%.
(5) Curing agent using organosulfonic acid curing agent, its viscosity is generally controlled at <200mPa.s, the content of water insoluble matter <0.1%, while there should be reversibility between freezing and subsequent dissolution. In order to ensure the stability of the sand can be used time and hardening speed, can choose "a + b" curing agent or according to the different seasons choose different acidity model curing agent.
(6) The coating adopts alcohol-based coating. The solid content of the coating is required to be high, the particle size of the powder is fine, and the refractoriness of the powder and binder is high, and the resistance to heat explosion is strong. Specific process performance requirements are: density 1.25~1.35 g/cm3; viscosity 6~7s; suspension (2h) >97%; brushability, leveling, permeability, crack resistance to be good, and high coating strength. For surface spheroidization with depth requirements of the casting, should use magnesium oxide coating.
4.2 Operation process procedures
4.21 Regenerated sand preparation is operated according to the requirements and process flow of resin sand regeneration equipment to obtain regenerated sand that meets the process requirements. Pay special attention to control the temperature of the regenerated sand when it enters the sand mixer, preferably at 25-35℃.
4.22 Adjustment of the amount of sand, resin and curing agent added
(1) Determination of the flow rate of the sand blender
According to the setting requirements of the sand blender, the flow rate should be measured at least once every four days under normal production conditions. Weigh the flow of sand, resin and curing agent in the same time respectively to master the time flow. and first adjust the sand flow rate according to the nominal flow rate of the sand mixer.
(2)Adjustment of resin amount
Adjust the amount of resin added according to the sand flow, the amount of resin added is generally controlled at 0.8~1.2% of the weight of the sand, with the upper limit taken for thick and large pieces and the lower limit taken for medium and small pieces.
(3)Adjustment of curing agent amount
The amount of curing agent added under normal circumstances and sand temperature and workshop environment temperature, generally control the amount of resin added 30 ~ 50%, high temperature to take the lower limit, low temperature to take the upper limit. Put sand time long large pieces of curing agent added to take the lower limit, in order to ensure that the resin sand has sufficient useable time.
(4)Adjustment and preparation of sand mixing machine
Strictly according to the "sand mixer operating procedures" for the daily maintenance of equipment, especially to clean up the blades and inner wall of the stirring cage in a timely manner. Every day before putting sand should be resin, curing agent pump separate cycle 1 ~ 2 minutes, and pay attention to check whether the curing agent to join the hole has crystallization blockage phenomenon.
4.23 Mould finishing and inspection.
(1) understand the process requirements of the castings produced, familiar with the process documents and process equipment.
(2) Check whether the mold core box is complete, and clear the excess residual buildup existing on the surface of the mold core box.
(3) Check whether the mold core box has missing corners and deformation, and whether the size is in accordance with the drawing requirements; check whether the live block and sprue are defective.
(4) Check whether the positioning pins and holes are suitable; whether the installation of mold starting device and lifting device is suitable.
(5) Check whether the bottom plate of the mold is straight and whether the size meets the requirements. The installation of metal plate must be flat, padded at all four corners, and guaranteed to be on a horizontal surface. Wooden base plate of the mold must be placed on the metal plate modeling, modeling should be checked before the base plate and the metal plate bond surface between the debris.
(6) whether the size of the sand box is appropriate, lifting lugs are securely available, large sand box for cracks and other defects.
(7) Prepare the cold iron, core support (cold iron, core support must be cooled to room temperature after baking before use) lifting tool, ventilation rope, sand block for sand filling. The surface of the cold iron used is best after processing or rough surface free of defects, generally thick large pieces of cold iron used not (8) more than 3 times, thin-walled pieces shall not exceed 5 times.
(9) All molds and core boxes are used after brushing the mold release agent.
4.24 Add sand and pounding
(1)The cold iron, live block, pouring mold sample, and the outgassing of mud core must be placed correctly according to the process requirements.
(2)Start the sand mixer after starting the dust collector, and the single stirring cage sand mixer should pay attention to remove the head sand first before the sand release operation.
(3) small and medium-sized pieces can be put sand from the mold sample, put sand should pay attention to prevent the movement of cold iron and live blocks, and pay attention to the corners, groove parts with a wooden stick pounding, other parts also have to use a wooden stick evenly pounding, especially to prevent local loose sand near the mold sample parts.
(4) large castings should start from a corner of the sand box to put sand, and pay attention to the appropriate adjustment of the amount of hardener added to extend the use of resin sand time. To put sand while pounding, from the corner of the sand box gradually along the other direction of the mold continuous expansion, until put the entire sand box. For large space sand box, resin sand can be placed with the shape of the mold sample to a certain thickness, generally control at 150~200mm (without filling sand block), must ensure that the resin sand of the gate, riser, air hole parts reach the height required by the process, the height of the gate, air hole parts can be used to meet the process requirements such as riser ring.
(5)At the end of the sand release, it should be noted that the tail sand should not be placed in the pouring mouth and air hole parts, but only in the unimportant place.
(6) Because the fluidity of resin sand is very good, pounding only requires fast speed, but not excessive force. Corners, grooves and other parts must be pounded.
(7) Tie the ventilation holes and control the distance of 30~50mm from the mold sample, which cannot be tied through.
4.25 Add sand block or other fillers due to the high cost of resin sand, in order to further reduce costs available waste sand block or other fillers to fill the unimportant space of the sand box, but should pay attention to the following issues:
(1) mold sample surface to be pounded, fill sand thickness of more than mold sample 100mm, before adding sand block or other fillers.
(2) no ceramic tube near the straight gate, near the cross sprue, near the air hole, the requirement of sand castings with high strength of thick wall and other parts of the sand block shall not be placed.
(3) filling sand block shall not have gaps between, should be pounded solid. The block size of filling sand block shall not be too large or too small, and shall be controlled between 50~200mm according to the size of different products.
4.3 Requirements of resin sand molding on mold process (resin sand production line):
Compared with clay sand, the appearance quality of resin sand casting depends on the quality of the mold, thus resin sand requires higher quality of the mold. The mold process makes it better adapted to the needs of resin sand molding, mainly in the following aspects.
(1) machining allowance: the hardened resin sand casting has better stiffness and higher dimensional accuracy, and is not easily deformed, so when choosing process parameters, a smaller machining allowance can be selected, thus reducing the consumption of metal solution and the cost of machining, which can improve the dimensional accuracy of the casting.
(2) mold pulling slope: resin sand in the starting mold already has a certain hardening strength, smaller retreat, larger friction, if the use of knocking methods to start the mold, easy to damage the mold, while the poor repairability of resin sand, starting mold, if damaged, more difficult to repair. When using resin sand molding, according to the actual production and product structure should increase the mold drawing slope, can smoothly start the mold, get quality With the market for castings product appearance quality requirements continue to improve, resin sand castings in quality advantages, will be increasingly important, resin sand casting production process, will also be rapid development and popularity.
(3) the surface roughness of the mold: the roughness of the mold surface plays a decisive role in the surface roughness of resin sand castings, and thus minimize the surface roughness of the mold, is an important measure to obtain high-quality castings.
Qingdao Sanzhuji Equipment Manufacturing Co., Ltd. specializes in the production of Green Sand Molding Line,Self-hardening sand molding line,foundry machines,Sand molding machine,Sand casting equipment,sand mixer,GS high efficiency rotary mixer,Resin sand mixer,no-bake resin sand mixer,Jolt squeeze molding machine/Jolt-squeezing moulding machines,Multi- Piston Moulding Machine/Hydraulic multi-piston moulding machine,sand casting molding machine,sand reclamation equipment，foundry molding machine,flaskless moulding machine,shot blasting machine,dust collector,according to the amount of old sand recovered Carry out plan customization, and provide sand reclamation equipment installation, commissioning, and training. Welcome guests to visit the factory.
In order to standardize the production process of resin sand casting, strictly implement the operation process, reduce the scrap and reduce the production cost of castings due to the violation of the process or improper operation, the production operation process procedures are formulated. This procedure is applicable to the whole process of production of all resin sand castings in the company and all kinds of operators related to it. The following is an excerpt for your reference and reading.
4.1 Process regulations
(1) the technical requirements or specifications of the main raw materials
(2) Raw sand (natural quartz sand)
Grain size: 40/70 mesh (medium to large pieces) or 50/100 mesh (general pieces).
Chemical composition: SiO2 >90%, mud content <0.2%~0.3%, water content <0.1~0.2%.
Micron content (below 140 mesh sieve) ≤0.5~1.0%, acid consumption value <5ml, scorch amount <5, particle shape: round or polygonal.
(3) regenerated sand scorching amount <3.0%; acid consumption value <2.0ml; PH value <5; 200 mesh sieve sump <1%; sump amount <0.2%; water content <0.2%.
(4) Furan resin contains 2.0~5.0% nitrogen; 24h tensile strength>1.5MPa; free formaldehyde<0.3%; viscosity<60mPa.s; density1.15~1.25 g/cm3; free phenol<0.3%.
(5) Curing agent using organosulfonic acid curing agent, its viscosity is generally controlled at <200mPa.s, the content of water insoluble matter <0.1%, while there should be reversibility between freezing and subsequent dissolution. In order to ensure the stability of the sand can be used time and hardening speed, can choose "a + b" curing agent or according to the different seasons choose different acidity model curing agent.
(6) The coating adopts alcohol-based coating. The solid content of the coating is required to be high, the particle size of the powder is fine, and the refractoriness of the powder and binder is high, and the resistance to heat explosion is strong. Specific process performance requirements are: density 1.25~1.35 g/cm3; viscosity 6~7s; suspension (2h) >97%; brushability, leveling, permeability, crack resistance to be good, and high coating strength. For surface spheroidization with depth requirements of the casting, should use magnesium oxide coating.
4.2 Operation process procedures
4.21 Regenerated sand preparation is operated according to the requirements and process flow of resin sand regeneration equipment to obtain regenerated sand that meets the process requirements. Pay special attention to control the temperature of the regenerated sand when it enters the sand mixer, preferably at 25-35℃.
4.22 Adjustment of the amount of sand, resin and curing agent added
(1) Determination of the flow rate of the sand blender
According to the setting requirements of the sand blender, the flow rate should be measured at least once every four days under normal production conditions. Weigh the flow of sand, resin and curing agent in the same time respectively to master the time flow. and first adjust the sand flow rate according to the nominal flow rate of the sand mixer.
(2)Adjustment of resin amount
Adjust the amount of resin added according to the sand flow, the amount of resin added is generally controlled at 0.8~1.2% of the weight of the sand, with the upper limit taken for thick and large pieces and the lower limit taken for medium and small pieces.
(3)Adjustment of curing agent amount
The amount of curing agent added under normal circumstances and sand temperature and workshop environment temperature, generally control the amount of resin added 30 ~ 50%, high temperature to take the lower limit, low temperature to take the upper limit. Put sand time long large pieces of curing agent added to take the lower limit, in order to ensure that the resin sand has sufficient useable time.
(4)Adjustment and preparation of sand mixing machine
Strictly according to the "sand mixer operating procedures" for the daily maintenance of equipment, especially to clean up the blades and inner wall of the stirring cage in a timely manner. Every day before putting sand should be resin, curing agent pump separate cycle 1 ~ 2 minutes, and pay attention to check whether the curing agent to join the hole has crystallization blockage phenomenon.
4.23 Mould finishing and inspection.
(1) understand the process requirements of the castings produced, familiar with the process documents and process equipment.
(2) Check whether the mold core box is complete, and clear the excess residual buildup existing on the surface of the mold core box.
(3) Check whether the mold core box has missing corners and deformation, and whether the size is in accordance with the drawing requirements; check whether the live block and sprue are defective.
(4) Check whether the positioning pins and holes are suitable; whether the installation of mold starting device and lifting device is suitable.
(5) Check whether the bottom plate of the mold is straight and whether the size meets the requirements. The installation of metal plate must be flat, padded at all four corners, and guaranteed to be on a horizontal surface. Wooden base plate of the mold must be placed on the metal plate modeling, modeling should be checked before the base plate and the metal plate bond surface between the debris.
(6) whether the size of the sand box is appropriate, lifting lugs are securely available, large sand box for cracks and other defects.
(7) Prepare the cold iron, core support (cold iron, core support must be cooled to room temperature after baking before use) lifting tool, ventilation rope, sand block for sand filling. The surface of the cold iron used is best after processing or rough surface free of defects, generally thick large pieces of cold iron used not (8) more than 3 times, thin-walled pieces shall not exceed 5 times.
(9) All molds and core boxes are used after brushing the mold release agent.
4.24 Add sand and pounding
(1)The cold iron, live block, pouring mold sample, and the outgassing of mud core must be placed correctly according to the process requirements.
(2)Start the sand mixer after starting the dust collector, and the single stirring cage sand mixer should pay attention to remove the head sand first before the sand release operation.
(3) small and medium-sized pieces can be put sand from the mold sample, put sand should pay attention to prevent the movement of cold iron and live blocks, and pay attention to the corners, groove parts with a wooden stick pounding, other parts also have to use a wooden stick evenly pounding, especially to prevent local loose sand near the mold sample parts.
(4) large castings should start from a corner of the sand box to put sand, and pay attention to the appropriate adjustment of the amount of hardener added to extend the use of resin sand time. To put sand while pounding, from the corner of the sand box gradually along the other direction of the mold continuous expansion, until put the entire sand box. For large space sand box, resin sand can be placed with the shape of the mold sample to a certain thickness, generally control at 150~200mm (without filling sand block), must ensure that the resin sand of the gate, riser, air hole parts reach the height required by the process, the height of the gate, air hole parts can be used to meet the process requirements such as riser ring.
(5)At the end of the sand release, it should be noted that the tail sand should not be placed in the pouring mouth and air hole parts, but only in the unimportant place.
(6) Because the fluidity of resin sand is very good, pounding only requires fast speed, but not excessive force. Corners, grooves and other parts must be pounded.
(7) Tie the ventilation holes and control the distance of 30~50mm from the mold sample, which cannot be tied through.
4.25 Add sand block or other fillers due to the high cost of resin sand, in order to further reduce costs available waste sand block or other fillers to fill the unimportant space of the sand box, but should pay attention to the following issues:
(1) mold sample surface to be pounded, fill sand thickness of more than mold sample 100mm, before adding sand block or other fillers.
(2) no ceramic tube near the straight gate, near the cross sprue, near the air hole, the requirement of sand castings with high strength of thick wall and other parts of the sand block shall not be placed.
(3) filling sand block shall not have gaps between, should be pounded solid. The block size of filling sand block shall not be too large or too small, and shall be controlled between 50~200mm according to the size of different products.
4.3 Requirements of resin sand molding on mold process (resin sand production line):
Compared with clay sand, the appearance quality of resin sand casting depends on the quality of the mold, thus resin sand requires higher quality of the mold. The mold process makes it better adapted to the needs of resin sand molding, mainly in the following aspects.
(1) machining allowance: the hardened resin sand casting has better stiffness and higher dimensional accuracy, and is not easily deformed, so when choosing process parameters, a smaller machining allowance can be selected, thus reducing the consumption of metal solution and the cost of machining, which can improve the dimensional accuracy of the casting.
(2) mold pulling slope: resin sand in the starting mold already has a certain hardening strength, smaller retreat, larger friction, if the use of knocking methods to start the mold, easy to damage the mold, while the poor repairability of resin sand, starting mold, if damaged, more difficult to repair. When using resin sand molding, according to the actual production and product structure should increase the mold drawing slope, can smoothly start the mold, get quality With the market for castings product appearance quality requirements continue to improve, resin sand castings in quality advantages, will be increasingly important, resin sand casting production process, will also be rapid development and popularity.
(3) the surface roughness of the mold: the roughness of the mold surface plays a decisive role in the surface roughness of resin sand castings, and thus minimize the surface roughness of the mold, is an important measure to obtain high-quality castings.
Qingdao Sanzhuji Equipment Manufacturing Co., Ltd. specializes in the production of Green Sand Molding Line,Self-hardening sand molding line,foundry machines,Sand molding machine,Sand casting equipment,sand mixer,GS high efficiency rotary mixer,Resin sand mixer,no-bake resin sand mixer,Jolt squeeze molding machine/Jolt-squeezing moulding machines,Multi- Piston Moulding Machine/Hydraulic multi-piston moulding machine,sand casting molding machine,sand reclamation equipment，foundry molding machine,flaskless moulding machine,shot blasting machine,dust collector,according to the amount of old sand recovered Carry out plan customization, and provide sand reclamation equipment installation, commissioning, and training. Welcome guests to visit the factory.
