Views: 684 Author: Site Editor Publish Time: 2020-01-21 Origin: Site
Supersonic flame is a high-temperature, high-speed combustion flame, generated by burning propane, propylene and other hydrocarbon-based gas or hydrogen and high-pressure oxygen in the combustion chamber, or in a special nozzle. And the speed of flame can reach Mach 5 (1500m/s. ) or above, commonly referred as HVOF (High-velocityoxygen-fuel). By feeding the powder axially into the flame, which could heat the sprayed particles to a molten or semi-molten state, and then accelerate up to 300-500m/s or more, the high-strength, dense and high-quality coatings could then be obtained. The supersonic flame has high speed but low temperature relatively. For WC-Co cemented carbide, it can effectively inhibit the decomposition of WC during the spraying process. So that not only the high bonding strength, the coating is also of high dense and excellent wear resistance. Its wear resistance greatly exceeds that of plasma spray coating, electroplated hard chromium layer or spray melt layer, and is equivalent to that of explosive spray coating. The flame is widely used in producing single-screw and twin-screw, and has been affirmed in actual use.
Screw cleaning is critical to product quality in modified plastics production, yet often overlooked. This article analyzes four common cleaning methods for twin-screw extruders—resin cleaning, disassembly and manual cleaning, flame cleaning, and water-based cleaning—covering their operational principles, key process steps, precautions, and limitations. It provides practical guidance for selecting and combining cleaning methods based on material characteristics, equipment condition, quality requirements, and cost-effectiveness, while emphasizing standardized operations and regular maintenance to extend equipment service life.
For PVC plastic extrusion production lines, feeding method selection depends on material form and process requirements. Three common systems are compared: spring feeders (quick to clean, suitable for frequent color changes but poor with high-filler powders), screw feeders (high flow rate and anti-bridging, ideal for high-filler powders but not for fiber-reinforced materials), and vacuum feeders (dust-free and closed-loop, best for cleanrooms and fiber reinforcement but limited at high output).
Most screw breakages are caused by the reasons mentioned above. Regular inspection of the gearbox, ensuring adequate heating temperature, avoiding material interruptions, strictly following formulas, and preventing foreign objects in raw materials can effectively reduce the risk of screw breakage.
This article cautions against pursuing excessively short injection molding cycles (e.g., 2.8 seconds), outlining 20 improper high-speed practices and their consequences. It covers material degradation, gas entrapment, mold and machine component fatigue, hydraulic system damage, and mechanical failures, emphasizing that aggressive cycle reduction compromises part quality and equipment reliability rather than yielding genuine efficiency gains.
On this National Day, Ningbo Superior Machinery extends our warmest wishes to clients, partners, and colleagues around the world.We grow with our nation, and we move forward because of you.May our country prosper, and may our partnerships stay green and lasting.Happy National Day!
The cooling behavior of highly crystalline polymers and the shrinkage stresses caused by uneven cooling. It explains how one-sided rapid cooling creates amorphous/crystalline imbalances, leading to warpage, internal stress, and reduced mechanical properties. The article also provides practical methods for detecting overcooling and recommends slowing or interrupting cooling to allow stress relief and annealing.
The bright full moon carries our sincere regards. On this beautiful Mid-Autumn Festival, Ningbo Superior Machinery wishs all partners and friends good health, happiness and a joyful reunion with your families.
