Part Ⅰ: Operation, Process and Maintenance of Extruder

1. The extruder is a high-pressure vessel machine. It uses high-pressure hydraulic fluid to generate pressure and drive the piston to move forward and backward, extruding tin solder into profiles. The pressure it generates is much higher than the load capacity of steam boilers. Therefore, operators must understand the severity of potential accidents, be familiar with and implement these safety regulations, and operate with full concentration.

2. The maximum operating process pressure load: 180 kg/cm² for 250-ton hydraulic presses and 200 kg/cm² for 300-ton hydraulic presses. Overloading beyond these values is strictly prohibited to avoid accidents.

3. Although travel limit switches are installed for the forward and backward strokes of the piston of horizontal extruders, operators must be alert to the potential failure of electrical switches. Thus, operators must not leave their posts and shall closely monitor the operation. In case of abnormalities, the machine must be shut down immediately for inspection.

4. If abnormal noise is heard during extrusion operation, the motor must be turned off immediately. The machine can only be restarted for production after the cause is identified and rectified. This prevents personal and equipment accidents.

5. After starting the motor, the extruder piston and extrusion rod must be operated for an idle stroke. Production operation with tin alloy round bars can only be carried out when the extrusion rod is aligned with the center of the extrusion cylinder cavity.

6. Before finishing work, operators must remove the tin skin from the end of the extrusion rod and embed the extrusion rod into the extrusion cylinder cavity by approximately 50mm before shutting down the machine.

7. All production preparations must be completed before startup, such as checking the temperature of the extrusion cylinder and the flux container. Operation can only be performed when these conditions are confirmed to meet the production process requirements.

8. The heating and heat preservation container for flux is also a pressure tank. It must be inspected to ensure it is in good condition, and the flux level in the tank shall be maintained at more than one-third of the tank capacity to enhance self-pressure and ensure smooth flux flow. The flux level in the tank shall be monitored regularly. When adding flux, the gas pressure in the tank must be completely released before opening the tank cover. After adding, the fastening ring must be properly secured to avoid personal injury.

9. If the end of the extrusion rod is found to be covered with a thick layer of tin skin during extrusion, it must be removed each time. Apply a small amount of engine oil to the end face (not excessive) to reduce friction during the stroke and prevent cold shut issues in thick tin wires. In particular, this avoids mechanical and personal accidents caused by excessive backstroke force of the extrusion rod.

10. Bringing moisture or dampness into the extrusion cylinder is strictly prohibited. This prevents explosions and personal injury, as well as serious bubble defects in the extruded thick tin wires.

1. Lead-free solder must be produced on dedicated equipment. Pre-startup preparations shall be completed before work: the preheating temperature of the extrusion cylinder shall not be lower than 55℃ at the rear part, and the mold part shall be maintained at 100±5℃. For high-melting-point alloys, the temperature shall be appropriately increased, subject to the decision and instruction of engineering and technical personnel.

2. Flux shall be melted and prepared outside the extruder. The melting furnace equipment shall include: A stainless steel pot or high-pressure aluminum alloy pot (without a lid), capable of melting 10 kg of flux raw materials.

3. An automatic stirrer with stainless steel screw and blades, equipped with a speed regulator (adjustable speed) and a control box.

4. An automatic temperature controller with a function to control the liquid flux temperature within 0-300℃, including supporting relays.

5. A circular electric furnace with power 0-4000W and outer diameter Φ≤300mm.

6. One stainless steel stirring rod, specification Φ8mm, length approximately 500mm.

7. Preparation Procedure: Set the temperature controller to 140℃. First melt the flux; after complete melting, insert a thermocouple for automatic liquid temperature control. When the fluxliquid temperature reaches 140℃, add activators. After all materials are melted, perform automatic stirring for no less than 30 minutes to volatilize all moisture, preventing excessive spattering and smoke during welding. Then let it stand for 4-5 minutes to allow residual substances in the flux to settle at the bottom of the pot. Filter through a stainless steel screen, slowly pour into the hydraulic press flux tank, and finally discard the approximately 1cm-high flux sediment at the bottom.

After starting the extruder, first verify the alignment between the extrusion rod and the center of the cylinder cavity by running an idle stroke. Formal startup can only be conducted after confirmation of accuracy; meanwhile, verify the reliability of the back travel limit switch.

When extruding the first tin ingot, monitor the extrusion pressure and wire output speed. If the pressure is ≥160 kg/cm² and the linear speed is slow, adjust the extrusion cylinder temperature immediately. Do not force operation to ensure safe and high-quality equipment operation.

For extruded thick tin wires of Φ12mm and Φ9mm, inspect whether the flux core hole diameter meets the standard. If it fails to meet quality requirements, adjust immediately. The operation key point: push the outer die piece forward to increase the hole diameter, and pull it backward to reduce the hole diameter.

A small amount of pure engine oil can be appropriately applied to the tin ingot before putting it into the extrusion cylinder (but not excessively) to reduce friction during the stroke. Excessive oil will cause quality problems such as peeling, bubbles, oil holes, and cold shut in thick wires, and also bring operational and quality issues to subsequent processes.

When producing different alloy products, residual materials of different compositions in the feeding cylinder (except SnIn) do not need to be cleaned and can be continuously extruded. However, the thick tin wires extruded from the first three new ingots must be cut off and scrapped. Samples shall be taken for component analysis, and formal production can only start after qualification.

When producing different types of lead-free tin materials, the scrap materials from each process (such as smelting, extrusion, wire drawing, packaging) shall be classified and stored in dedicated containers. Especially for precious metals such as silver and indium, mixing is strictly prohibited to avoid quality and economic accidents.

When extruding hard (lead-free) solder (containing bismuth, antimony, tellurium, copper, etc.), reduce the wire output speed to prevent wire cracking and subsequent wire drawing difficulties.

If the flux core of the extruded thick tin wire is deviated from the center or irregular, and adjustment is ineffective, disassemble the mold to inspect whether the mold nozzle and mold rod are damaged, cracked, or bent. If so, replace with a new mold and restart production.

The flux melting container on the extruder shall be disassembled and cleaned regularly (preferably every 15 days) to remove precipitated aged scale, preventing pipeline blockage and quality accidents such as flux interruption in solder wires. When the flux level in the container is lower than 1/3, add new flux. Before adding, first release the air pressure in the tank, then open the cover for operation, and pay attention to production safety.

Just as you would perform careful maintenance on your car after a certain period of use or mileage, the extruder used for solder production also requires maintenance after a period of operation.

1. Hydraulic Oil: When filling hydraulic oil into a new machine, the oil cylinder must be thoroughly cleaned and dried to prevent the hydraulic oil from emulsifying when the machine is started. After 6 to 12 months of use, inspect the oil quality regularly to avoid excessive oil viscosity affecting machine operation. If the oil viscosity is too high, replace with new hydraulic oil (half replacement is acceptable).

2. Lubricating Oil Addition: Equipment manufacturers have reserved oil injection ports at the guide pillars of the extruder to prevent dryness after long-term operation. It is recommended to add ordinary lubricating oil every one to three months. Secondly, lubricating oil must be added to the air cylinder to ensure its normal operation.