Sand spraying machine is a specialized equipment used in precision casting, ceramics and other industries to coat wax molds or shells with sand layers (such as mullite sand, quartz sand, etc.). Its core function is to evenly adhere sand particles to the surface of the workpiece to be processed through a specific sand spraying method, forming a coating with certain strength and breathability, laying the foundation for subsequent shell manufacturing or processing processes. The following is a detailed introduction about the sanding machine:
1、 Working principle
The working process of the sand shower machine mainly revolves around "uniform adhesion of sand particles":
Workpiece fixation and transportation: Fix the wax mold or shell to be sandblasted (usually coated with a coating layer) on the fixture, and transport it to the sandblasting area through conveyor belts, turntables, or robotic arms.
2. Sand spraying/coating: The equipment uses power devices such as sand buckets, conveying pumps, or compressed air to spray, sprinkle, or fluidized bed sand particles (with different particle sizes selected according to process requirements) onto the surface of the workpiece.
3. Uniform adhesion: Under the action of gravity, airflow, or centrifugal force, sand particles come into contact with and embed into the wet coating layer on the surface of the workpiece, forming a uniform sand layer. Some equipment will cooperate with vibration or rotation mechanisms to ensure that sand particles can fully adhere to complex surfaces, grooves, and other parts of the workpiece, avoiding sand leakage or accumulation.
4. Residual sand recovery: Unattached sand particles are collected through the bottom recovery device (such as sieve or funnel), and after screening, they can be recycled to reduce sand waste.
2、 Structural composition
The structure of the sanding machine varies depending on the degree of automation and application scenarios, but the core components generally include:
1. Rack and conveyor system: As the basic framework of the equipment, it supports the operation of various components; The conveying system (such as turntable, conveyor belt, robotic arm) is responsible for the movement and positioning of the workpiece, ensuring that the workpiece passes through the sand spraying area according to the preset path.
2. Sand supply and conveying device: including sand hopper (storing sand particles), conveying pump (pneumatic or electric, conveying sand particles to the sand spraying nozzle), pipeline, etc., controlling the supply amount and speed of sand particles.
3. Sanding mechanism: core working component, common forms include:
Nozzle type: sand particles are sprayed from the nozzle through high-pressure airflow, forming a fan-shaped or columnar sand flow that covers the surface of the workpiece;
Drip trough type: immerse or skim the workpiece into a sand filled trough, and use gravity to make the sand particles adhere;
Fluidized bed type: Sand particles are suspended by airflow, and the workpiece is attached when passing through the suspended sand layer.
4. Vibration/auxiliary mechanism: Some equipment is equipped with vibration devices (such as workbench vibration) to promote sand particles to adhere more tightly and evenly to the surface of the workpiece, especially suitable for workpieces with complex shapes.
5. Sand material recycling and screening system: composed of a recycling funnel, screen, sand storage box, etc., it recovers unused sand particles and removes impurities to achieve sand material recycling.
6. Control system: By using PLC (programmable logic controller) or touch screen to control parameters such as conveying speed, sand supply, and sand spraying time, some automated equipment can achieve multi process linkage (such as cooperating with coating machines).
3、 Equipment features
1. High uniformity of sand layer: By accurately controlling the sand flow rate, workpiece movement speed, and auxiliary vibration, the thickness of the sand layer is ensured to be consistent, reducing shell defects (such as cracks and deformation) caused by uneven sand layer.
2. Strong adaptability: The sanding method and tooling can be adjusted according to the size and shape of the workpiece (flat, curved, irregular parts) to meet the process requirements of different products.
3. Flexible degree of automation: There are both simple manual equipment (suitable for small batches and complex parts) and fully automatic production lines (such as combining with robots for loading and unloading, and forming a linkage line with coating machines) to improve production efficiency.
4. High utilization rate of sand: equipped with an efficient recycling system, reducing sand waste and lowering production costs.