Characteristics of Polyethylene

Characteristics of Polyethylene

Polyethylene is a milky white plastic, waxy and translucent surface is ideal wire and cable insulation and jacketing materials. Its main advantages are:

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(1) excellent electrical properties. High insulation resistance and electric strength; over a wide frequency range, the dielectric constant ε and the dielectric loss tangent value of tgδ and substantially independent of frequency change, as the communication cable insulation materials are almost ideal one medium.

Better

(2) mechanical properties, full flexibility, and tough, resistant capacitive good.

(3) heat aging resistance, low temperature resistance, cold resistance and chemical stability.

(4) good water resistance, low moisture absorption, insulation resistance immersed in water is generally not declined.

(5) as the non-polar materials, a large gas permeability, the permeability is low-density polyethylene is the most excellent in various plastics.

(6) the proportion of light, its specific gravity less than one. LDPE is particularly prominent, about 0.92g / cm3; large low pressure polyethylene, although its density is only about 0.94g / cm3.

(7) has a good processing performance, easy-to-melt plasticizing, and difficult to break down, cooling easy molding, product geometry and structure size easy to control.

(8) with its light weight wire and cable production, use, laying convenient, easy fitting.

But there are many disadvantages of polyethylene: the softening temperature is low; contact with the flame burning and melting easy, and emit the same smell when burning paraffin; poor resistance to environmental stress cracking resistance and creep resistance, as the seabed in polyethylene cables and larger gap (especially vertical laying) when the cable insulation and sheathing materials using special attention. Wire and cable polyethylene plastic

(A) General insulated polyethylene plastic

（1）Only the polyethylene resin and an antioxidant composition.

(2) weather polyethylene plastic

Mainly composed of a polyethylene resin, an antioxidant, and carbon black composition. Weathering performance is good or bad depends on the particle size of the carbon black content, and dispersion.

(3) resistance to environmental stress cracking of polyethylene plastic

Melt index of 0.3 or less, not too wide molecular weight distribution polyethylene; irradiation or chemical cross-linking of the polyethylene for.

(4) high-voltage insulated with polyethylene plastic

Polyethylene plastic for high voltage cable insulation highly pure, still need to add a voltage stabilizer and using a special extrusion machine, avoid pores produce to inhibit resin discharge, increase polyethylene arc resistance, corrosion resistance and electrical corona .

(5) semi-conductive polyethylene plastic

Semi-conductive polyethylene plastic is added conductive carbon black in polyethylene obtained, the general should be fine particle size carbon black, high structure.

(6) Thermoplastic LSZH polyolefin cable material

This kind of cable is a polyethylene resin-based material, adding quality and efficient halogen-free non-toxic flame retardants, smoke suppressants, heat stabilizers, fungicides, additives, coloring agents modified by mixing, plasticizing , granulating

PC plastic injection molding processing technology is introduced

PC known as polycarbonate, because of its excellent mechanical properties, commonly known as bulletproof glue. PC has high mechanical strength, wide range of temperature, electric insulation performance is good, but the arc performance unchanged), good dimensional stability and transparency, etc. In the casing electrician products, all structure, electronic products are widely used. PC modified product is more, there are usually added glass fiber (GF), mineral filler (M), chemical flame retardants, and other plastic, etc. PC's liquidity is poorer, the processing temperature is higher, so the many levels of modified materials processing need special plasticizing injection structure.

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1, the processing of plastic PC bibulous rate is larger, must be preheated before processing dry, pure PC 120 ℃ drying, modified PC generally with 110 ℃ drying temperature more than 4 hours. The drying time can't more than 10 hours. Generally available to the vacant extrusion method to determine whether a dry enough. The use of reworked material ratio can reach 20%. In some cases, may use reworked material, 100% of the actual quantity depends on product quality requirements. Reworked material cannot mix different masterbatch, otherwise it will seriously damage the nature of the finished product.

2, selection of injection molding machine now PC products due to cost and other reasons, the use of modified materials, especially the electric products, still must increase the fireproof performance, in the flame retardant PC and other plastic molding, alloy products is mix well to the requirement of plastic injection machine plasticizing system, corrosion resistance, the conventional plasticizing screw hard, when the choose and buy, be sure to explain in advance. Ramada company has a dedicated PC screw for customers to choose.

3, mold and gate design Common mold temperature is 80-100 ℃, and glass fiber is 100-130 ℃, small products available needle gate, the gate depth should be the thickest part of 70%, other gate are circular and rectangular. Gate the bigger the better, in order to reduce the plastic shear caused by excessive defects. The depth of the vent should be less than 0.03 0.06 mm, port as far as possible short and round. Draft is generally about 30 '- 1 °.

4, melt temperature can be used for empty injections to determine processing temperature. General PC processing temperature is 270-270 ℃, some modification or low molecular weight PC for 230-230 ℃. 5, see more with the fast injection speed rate of injection molding, such as electrical switch parts. Common for slow and rapid prototyping.

6, back pressure around 10 bar back pressure, without gas lines and color mixture can be appropriately reduced. 7, residence time, At high temperatures for a long time, material qualitative, cut out CO2, become yellow. Don't use LDPE, POM, ABS or PA cleaning barrel. Application of PS. 8, matters needing attention Some modified PC, due to too many times (lower molecular weight) or ingredients mixing unevenly, easy generation dark brown liquid.

CNMOULDING the 6S Quality Management System

"6S management" 5S expansion by Japanese companies come, is a modern facility effective site management concepts and methods, its role is: to improve the efficiency, quality assurance, clean and orderly work environment, prevention, and ensure safety. Nature is an execution 6S corporate culture, emphasizing the culture, not afraid of difficulties discipline, think to do, to do a good job, work as a basis for the implementation of 6S, can provide high-quality management platform for other management activities.

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6S content

Finishing (SEIRI) - the area of ​​any article into the workplace and does not need to be necessary, in addition it is necessary to leave the other are eliminated. Objective: To make room, space utilization, prevent misuse, create refreshing workplace.

Rectification (SEITON) - necessary to stay with the position of the items placed in accordance with the provisions, and placed them neatly labeled. Objective: Workplace glance, eliminating time looking for items, neat working environment, eliminating excessive backlog items.

Cleaning (SEISO) - the visible and invisible in the workplace where cleaned, keep the workplace clean and beautiful environment. Objective: stable quality, reduce industrial injuries.

Clean (SEIKETSU) - maintain above 3S results.

Literacy (SHITSUKE) - each member to develop good habits, and follow the rules work, actively cultivate the spirit (also known as habitual). Objective: To cultivate good habits, to comply with the rules of the staff, and create a members spirit.

Security (SECURITY) - emphasis on full safety education, safety first at all times have the concept of preventive measures. Objective: To establish a safe production environment, all work should be based on the premise of safety.

Because the Japanese are beginning the Roman alphabet "S", and therefore referred to as the "6S".

6S relationship

Associated with each other, organize, straighten, sweep is the specific content; clean is institutionalized and standardized; cleaning refers to the bypass? Keep 3S level, literacy is a habit, discipline, rules, rigorous; safety is the foundation of respect for life, to prevent illegal. Finishing: distinction and do not want to, just the right amount left to live, do not clean out, saving space; rectification: the things you want to be positioned in accordance with regulations, as neatly and accurately identify, save time; cleaning: the workplace remove dirt and prevent the occurrence of dirt to keep the workplace clean, equipment inspection and maintenance to ensure the quality and efficiency of the technology; clean: 3S will work standardization and institutionalization, and maintain results, perseverance; literacy: Everyone acting in accordance with the provisions to develop good habits, the pursuit of the highest realm. Safety: Do not illegal, respect for life.

6S management implementation principles:

(A) efficiency: set-location is a prerequisite to improve work efficiency;

(2) holders of property: humane, global compliance and maintain;

(3) appearance: as a product - as culture - the conquest of the customer base. Management philosophy to adapt to the scene scenes show people uncomfortable, moved.

6S management of the essence:

(1) Full participation: chairman - frontline staff, all departments: production, technology, line pipe, finance, logistics;

(2) the whole process: the whole product development - the abolition of the life cycle

Everyone keep - improve - keep - Management Activities

(3) full efficiency: overall efficiency, challenge the work of the limit.

Only a starting point not the end.

The benefits of the implementation of 6S

(A) enhance the corporate image - neat and clean work environment, to attract customers and boost confidence;

(2) reduce waste: staff entrance exhibits area, the time taken sieve, space debris misplacing, nowhere else to put.

(3) improve the efficiency: good environment, mood, placed in an orderly, time-saving, reducing handling operations.

(4) Quality assurance: things seriously rigorous, eliminate sloppy, reliable quality.

(5) Security: channel flow, wide and bright, serious and responsible person, less accidents.

(6) increase the life of equipment: cleaning, inspection, maintenance, maintenance;

(7) to reduce costs: reduce leaking, reduce round-trip transportation;

(8) delivery standards: clear, obvious anomalies of timely adjustment operations.

6S implementation steps:

(1) Decision - swearing;

(2) Organization - File "learning", the Selection Committee, the implementation of office, the implementation team was established prior to the teams at all levels to work on Wednesday reported that the implementation of the list to do.

(3) the formulation of policies, objectives --6S policy is now standardized on-site materials, improve the overall quality, the need for signage, hanging in the workshop;

"6S management" extended 5S comes from Japanese companies, is a modern facility effective site management concepts and methods, and other well-known headhunter headhunting was adopted flames. Its role is: to improve the efficiency, quality assurance, clean and orderly work environment, prevention, and ensure safety.

1. Finishing (SEIRI) - the area of ​​any article into the workplace and does not need to be necessary, in addition it is necessary to leave the other are eliminated.

Objective: To make room, space utilization, prevent misuse, create refreshing workplace.

2. Rectification (SEITON) - necessary to stay with the position of the items placed in accordance with the provisions, and placed them neatly labeled.

Objective: Workplace glance, eliminating time looking for items, neat working environment, eliminating excessive backlog items.

3. Cleaning (SEISO) - the visible and invisible in the workplace where cleaned, keep the workplace clean and beautiful environment.

Objective: stable quality, reduce industrial injuries.

4. Clean (SEIKETSU) - maintain above 3S results.

5. Literacy (SHITSUKE) - each member to develop good habits, and follow the rules work, actively cultivate the spirit (also known as habitual).

Objective: To cultivate good habits, to comply with the rules of the staff, and create a members spirit.

6. Security (SECURITY) - emphasis on full safety education, safety first at all times have the concept of preventive measures.

Objective: To establish a safe production environment, all work should be based on the premise of safety.

ISO9000 Quality Management System Certification Program

Mold quality control points

Mold quality control points

A, the rationality of the mould design

Structure design is reasonable is the key to the quality of a complete set of mold, mold production cycle, so for the mold structure design and manufacturing process must attach great importance to, be sure to do reasonable as far as possible, to get twice the result with half the effort. Thus design it necessary to pay attention to the following:

1. When the mould structure design should pay attention to how to make the production process, easy to do. Plastic pieces of the size of some key parts (such as dimension, high precision size or contract) in areas such as the uneven tolerance reserve the direction of the steel material selection, so that need change after test module and have a chance of correction, and avoid possible welding such as remedies.

2. Mold design for putting small and more or mold eccentric structure, mould should be under the guide pillar structure. The launch of the hole for multiple rib ventilation window can decorate a few first, but pay attention to the position of the reserved (avoid water), so that can increase when necessary to launch holes or increase the rib Angle so that the mold. Strict in plastic parts shape and can't feed, try to adopt the way of diving or putting diving feed.

3. The mould design is completed, need comprehensive review all drawing size especially mutual need to fit the size and type bit size accurate, can only be a formal processing drawings, all employees participating in the mold production to each process control according to the requirements of size. Second, the quality control of mold material

We manufacture I mold are small batch or single production, processing process is complex, manufacturing cycle is long, the mould parts of raw materials for processing using even affected the quality of the mould of a complete set of, according to the present production condition, from the mold production necessary

The aspects of mould materials for quality control.

1. Should choose fixed, with stable quality assurance materials suppliers. For key mold parts material, required to provide product certification; When necessary for material composition test, inspection quality inspection, etc.

2. The material into the factory inspection work earnestly. Requirements:

1) material chemical composition is correct. (use spark discriminant);

2) good quality of materials and forging surface smooth, no obvious crack folding, scarring, slag inclusion, open side after texture

Even, no cracks, porosity, slag inclusion and other surface; 3) delivery hardness appropriate size (HRC26-32) right;

4) die set to check the datum, the parting surface precision, A and B plate material quality, and provide mould frame factory inspection requirements

The report.

3. The production process at any time to monitor quality of materials, die set, found that the problem is detailed record and feedback management personnel handling.

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Injection of new technology introduction

Injection of new technology introduction

1. Nitrogen gas-assisted injection

      Nitrogen gas-assisted injection system, this advanced systems and technology, is to control the system directly injected into the mold cavity via a segmented plasticized plastic wrap nitrogen pressure on the plastic parts caused by internal expansion hollow, but still keep the shape of the product surface intact. Application of nitrogen-assisted injection molding technology,Has the following advantages: 1) plastic materials savings, savings rates can be as high as 30%.

2) shorten the production cycle time.

3) reducing the clamping pressure injection molding machine can be as high as 30%.

4) improve the working life of the injection molding machine.

5) reducing the pressure in the mold cavity, the mold of loss reduction and improving the working life of the die.

6) for certain plastic products, mold can be aluminum metal.

7) Reduce stress, product warpage problems and improve the density of the plastic parts.

8) to solve the problem and eliminate the product surface has shrunk.

9) to simplify the cumbersome design products. 10) Reduce consumption of injection molding machines.

11) lower investment cost injection molding machine and mold development.

  12) reduce the production cost.

Nitrogen gas-assisted injection molding technology can be applied to a variety of plastic products, such as televisions or stereo housing, automotive plastic products, furniture, bathroom, kitchenware, household appliances and daily necessities, various types of plastic boxes and toys. Nitrogen gas-assisted injection molding technology in the injection molding industry must be subject to a wide range of applications

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Automotive plastic parts

China's auto industry as an important pillar industry of the national economy, plastic molding process due to its low consumption, the high efficiency, the use recyclable. Automotive plastic covers PP, PVC, ABS, PA, PC, PE, etc. using plastic car parts to replace metal and alloy material parts, not only can the car design more humane, diversification, improve safety, comfort, ornamental, easy assembly and maintenance, more importantly, reduce vehicle weight and reduce fuel consumption and hydrocarbon emissions.

Automotive plastic products and materials

A polyurethane foam polyurethane foam products are widely used in the automotive interior components and absorb vibrations. Its main products are: instrument panels, mirrors frames, bumpers, seat cushions, headrests, steering wheel, control box, dashboard anti-vibration pads, front and rear pillar trim, middle pillar trim, roof lining front, window frames, decorative ceiling and side roof frame, door linings, sun visors, the top shelf decoration.

Second, the car performance parts engineering plastics manufacturing auto parts more common parts which are: the radiator grille (its material ABS, 20% glass fiber reinforced polypropylene), air filter shell (poly propylene), the line inside the lid (polypropylene), dashboard (polypropylene), crankcase cover (nylon 6), timing gear chain box (polypropylene), timing gear (30% glass fiber reinforced POM), mudguard (nylon R-RIM) and the like.

  Third, the plastic matrix composite plastic composites such as automotive products, SMC, DX (POM composite materials) started for the manufacture of automotive structural parts, reducing vehicle weight plays an important role.

PPS material

PPS material

PPS is a polymer compound having a phenylthio group on the main chain, due to its structure and the sulfur are alternately connected to a benzene ring, the molecular chain having a high rigidity and regularity, PPS is a crystalline polymer and thus, has many excellent properties, such as heat resistance, rigidity, flame retardancy and electrical insulation. Lone pair electrons of the sulfur atom such PPS and glass fiber, an inorganic filler and a metal having good affinity for easy-reinforced composite made ​​from a variety of materials and alloys

One, PPS performance

1, physical and mechanical properties of PPS is a white, crystalline high polymer density of 1.34. Excellent mechanical properties, tensile strength and bending strength than PA, PC, PBT, etc., with a high rigidity and resistance to creep, but brittle, low notched impact strength, lower than PA, PC, PBT higher than POM. After the addition of glass fiber reinforced its better mechanical properties. PPS case of inert material, non-toxic.

2, since the thermal properties of the PPS polymer is a crystalline, the maximum degree of crystallinity of up to 65%, and a crystallization temperature of 127 ℃, a melting point of 286 ℃, thermal deformation temperature 260 ℃, 430-460 ℃ in air than before decomposition, thermal stability far beyond the PA, PBT, POM and other engineering plastics, long-term use in thermoplastics highest temperature up to 220-240 ℃. PPS also has good thermal insulation and flame resistance, the critical oxygen index and PVC equivalent of up to 47%, without adding flame retardant, PPS can be achieved UL94-V0 grade level.

3, the molecular structure of the electrical properties of PPS symmetry, polarity, low water absorption, so its very good electrical insulating properties compared with other engineering plastics, small dielectric constant, arc resistance equivalent to thermosetting plastics, high temperature, high under wet conditions such as frequency, PPS can maintain good electrical insulating properties. Adding conductive fillers, conductive PPS can be obtained a composite material for the anti-static and electromagnetic shielding.

4, since the chemical resistance of PPS has a high degree of crystallinity, so it has excellent chemical resistance, below 200 ℃ insoluble in any organic solvent, in addition to strong oxidizing acids, but may be subjected to various types of acids, bases, salts erosion at high temperature after long-term immersion by a variety of chemicals, but also to maintain a high strength after PTFE. PPS also has good resistance to weathering resistance and radio.

Mold material

PPS higher processing temperature, a temperature of plastic material 290-330 ℃, mold temperature of 130-180 ℃, in most cases, while PPS reinforced by glass fiber, containing a relatively large amount of glass fibers, wear problems must be considered, so the mold material should be 140-150 ℃ as a benchmark, the appropriate choice of alloy materials, such as SK, SKD, SKH, etc., hardness HRC60-65, surface plating.