Focus on the development of polishing wheels

With the increasing application of industrial textiles, the application of non-woven composites has become increasingly apparent. Now we will introduce specific development cases for polishing wheel products.

The polishing wheel is processed on industrial products, especially in the production process of light industry and machinery products. It is suitable for the polishing of aluminum plates, stainless steel plates and high-quality products. It plays a key role in improving the surface quality of products. effect. At present, China generally adopts polishing wheels with viscose or polishing paste on the surface of the product. Because the corundum is easily detached and the viscous sand is not uniform, it causes problems such as low production efficiency, high energy consumption, high labor intensity, poor sanitary conditions, etc. At the same time, it also consumes a large amount of cotton cloth, and the surface quality of the processed product is poor. Low accuracy.

Since the 1950s, industrialized countries such as Europe, the United States, Japan, etc. have widely adopted non-woven cloth and synthetic resin composite polishing tools. It has the advantages of high cutting efficiency, good surface treatment effect, long service life, and low sand fall. It is suitable for batch production of automated production processes.

The following describes the production process of the new polishing material. There are roughly two processing methods: viscous and sand reinforcement.

The viscous sand production process utilizes synthetic fiber as raw material, non-woven fabric production process, and a non-woven mat having a certain thickness and high bulkiness. The abrasive and binder are then evenly sprayed and compounded onto the non-woven mat, after being dried. Depending on the adhesive, the abrasive adheres to the fibers and forms a felt with a certain throwing ability.

1. Raw material specifications generally use PA6 or PA66 staple fiber, with fineness of 9-15D and length of 51-65mm. In order to achieve high loftiness, the fiber should have high curl. Generally, 20 crimps or more, or spiral crimped fibers; at the same time, fiber lubricants are less likely to have strong adhesion when sand is bonded.

2. The manufacturing process of non-woven felt is as follows: fiber open cleaning - carding - web forming - spraying adhesive - drying room - reverse side spraying adhesive - drying room - trimming into rolls. It should be noted that: mechanical mesh must be added after the mechanical messy mechanism, or air-laid, spray-bonded air spray and sticky and airless spray, the adhesive is acrylic milk and acrylate and vinyl acetate copolymer emulsion .

3. Sticky sand specifications require non-woven felt as the skeleton, which is sprayed with various fineness of silicon carbide (TL), corundum (GZ), ferric oxide (Fe2O3), alumina, etc. Abrasive fineness About 80-320 mesh, spray adhesive at the same time, and then solidify the abrasive and fiber after solidification, so that the product has a certain degree of sanding grinding capacity of the sand felt.

(1) Adhesive: This adhesive is different from the adhesive for producing nonwoven felt, the former being an emulsion adhesive and the latter being a solvent adhesive. In order to make the adhesion between the abrasive and the fiber firmly, and because of the heat generated during the polishing process, the surface of the polishing wheel is up to 150~180°C. Therefore, in addition to the good bonding ability, the adhesive must also have Has a higher heat resistance, the current general use of modified phenolphthalein resin, epoxy resin and polyurethane resin.

(2) Sticky sand: It is generally completed on a special post-processing composite equipment. In order to ensure the uniformity of the abrasive on the product, the method of applying the abrasive is particularly important. At present, the dusting method is generally adopted. The structure is a hopper with an abrasive material on the upper surface, and a discharge roller with a flexible wire cloth is mounted under the hopper. The discharge roller rotates, and the abrasive material uniformly falls into the clothing cloth on the discharge roller side. A vibrator with a wire brush was installed, and the abrasive falling on the wire cloth was peeled off by vibration and dropped onto the non-woven felt. Another method uses a spray gun to spray on the non-woven felt, but it is difficult to ensure the uniformity of the abrasive, abrasive wear on the nozzle is also large, the abrasive dusting or sandblasting, then spray adhesive to make the abrasive and fiber firmly stick Finally, a certain practical value of the grinding wheel is formed.

4. Molding requirements Finally, the grinding wheel is reprocessed into various types of polishing wheels. It can be divided into four types: shot-type, laminated, pleated, and shaft-attached.

Shot Type: Cuts the felt into long squares of the required size. Arranged radially around the core. The inner ring is made of adhesive, and its density increases from the outside to the inside.

Laminated type: Cuts the felt into a layer of the required size, and laminates the compacted product with uniform density inside and outside.

Pleated type: The felt is cut into rectangular blocks of the required size, and the corrugated ring is fixed with a hexagonal steel buckle.

Attached Shaft Type: The long squares that cut the felt into the required size are arranged radially around the core and stuck into the central shaft to form a solid.

The precision of the work surface of the felt is better than that of the cloth, and the surface is smooth, the wear is small, and the sand falling is small, which is suitable for mass production of the mechanized production; the disadvantage is that the abrasive and the fiber are only bonded by the adhesive and bonded. The point is small and there is some abrasive shedding.

Another method of the sand reinforcement production process is the sand reinforcement method. In order to reduce the disadvantages of sand falling, foreign sand grinding wheels began to be developed in the 1970s. The sand bar is a kind of chemical fiber containing emery abrasive, made of sand felt and emery cloth with grit abrasive, and then assembled into a polishing wheel with certain gap and elasticity. The sand bar wheel has a stronger cutting force than the viscous sand wheel, and has adequate cogging and cushioning properties, so that the work surface can obtain a higher finish. At present, there are foreign PVA sand bars, PET sand bars, PA sand bars.

The manufacturing process of PVA sand bars can be decomposed into three major processes: the production of sand-containing fibers—the production of sand-containing fiber sand felts and emery cloth—forming.

1. Wet spinning is used for the production of sandy fibers, and a certain proportion of abrasive is added to the preparation of the raw liquid. The key is to solve the problem of sedimentation with a larger proportion of abrasives. Generally, additives and mixers can be used. At the same time, the contradiction between the abrasive and the diameter of the spinneret is required to solve the problem. Generally, a special spinneret is selected.

2. The production of sand-containing fiber sand felt and emery cloth Because fiber contains about 30 to 50% of abrasive material, the fiber ratio is large and the fiber is thick, which makes the fiber curling difficult. Therefore, we need to soften the fiber and make it to conventional non-woven equipment. Professional transformation to meet the technical requirements of the product.

The production process of emery cloth is: fiber softening treatment - fiber opening - fiber pre-carding - fiber air flow - adding sand - impregnation - drying and setting - slitting into rolls.

Its product specifications: 100 ~ 200g/m2, thickness of 2 ~ 4mm, adhesives can be 3 ~ 5% PVA formal resin and other thermal resins.

The felt production process is: fiber softening treatment - fiber opening - fiber pre-carding - fiber air-laid network - pre-acupuncture - the main acupuncture - into a roll - impregnated adhesive - drying and setting - into a roll.

Its product specifications are: 250 ~ 300g/m2, thickness of 4 ~ 5mm, the adhesive can also be 3 ~ 5% PVA formaldehyde resin and other thermal resins.

If a particularly coarse fiber is produced (150D), it can be produced using a wet process and produced using the hot pressurization cure method.

3. The molding process is the same as the sand molding process and will not be described here.

The process of polishing cloth production process is: spray cotton - scouring pad - polishing cloth.

The rubber-sprayed cotton roll product (adjusted for raw materials) is unwound - dipping - the first sandblasting - drying - the second sand blasting - drying - trimming - molding - quality inspection packaging - scouring pad.

Scouring cloth into a roll product (raw material adjustment) rewinding - dipping - trimming - forming - hydraulic drying - stamping - quality inspection packaging - polishing cloth.

Grinding wheel equipment details opener - opening machine - carding machine - cross lapping machine - conveyor - glue dispenser (2) - dryer - trimming coiler - control box (2) - heating furnace - calendering Machine - Acupuncture Machine - Adhesive Dispenser (2) - Three-layer Dryer - Resin Stirring and Extracting Machine - Straight-cutting machine - Rolling machine - Grinding wheel drying machine - Grinding wheel punching machine Spray gum, scouring pad 、Grinding wheel quality standard 1. Weight CV value: 5% or less 2. Thickness CV value: less than 10% 3. Spray rubber: 100”, scouring pad 50”, grinding wheel 50”

4. Finished product strength ratio is less than CD:MD = 1.6:1

5. Must not have cloud spots, overlapping marks 6. Single fiber rate is greater than 96%

7. The raw material loss rate is less than 5%

8. The product qualification rate is greater than 96%

Applicable raw materials and accessories fiber: NYLON 6, NYLON 66, PET (6-15Den, 51-76mm)

Resins: External conditions of acrylates, epoxy resins, phenolic resins, auxiliaries

1. Land area (including office, raw material warehouse, finished product warehouse, tool room): L=54M, B=51M;

2. Electric power: 217KW;

3. Heat medium oil furnace: 1 million kcal/hour;

4. Water pressure: more than 1.5KG/SQ.CM;

5. Air pressure: more than 6KG/SQ.CM;

6. Labor: 30 people;

Product use 1. Spray-bonded cotton: Industrial filter cloth (eg spray paint, chemical fiber spinning filter, industrial air-conditioner filter, household air-conditioner filter); clothing cloth (such as: female bra lining; coat shoulder lining); car interior lining (such as: door inner panel, roof inner lining)

2. Scouring cloth: household use (such as: bathroom ceramic tile, bowl container, wash hands); industrial use (such as: plating surface polishing, gold and silver jewelry surface polishing)

3. Grinding wheel: industrial (such as: stainless steel, doors and windows, square tubes, construction hardware, metal objects, electroplating, mechanical products, hull shells, wood utensils surface polishing, hand tools, elevators, escalators); life use (such as: food Cabinets, cooking cabinets, kitchen utensils stainless steel cutlery, knives, forks, pots, plates); craft use (such as: antique copper processing, strap, case, belt buckle, eye box, jewelry box); sports (such as: golf Head sports equipment, bicycles)

4. Polishing shaft wheel: industrial (such as: stainless steel plate, wood); agricultural products (such as: taro, grapes)

The proportion of raw materials, ingredients formula 1. Pen Jiaomian PET large chemical fiber 15%; 35% of chemical fiber; small chemical fiber 50%;

PA chemical fiber 100% - grinding wheel acrylic resin 0.17KG fiber per square meter with 0.075KG resin (200G spray rubber meter)

2. The scouring pad sprayed cotton accounted for 51.6% of the weight, the rest of the corundum sand 0.16KG; epoxy resin 0.16KG; solvent 0.16KG; color fiber 0.004KG;

3. The weight of the sprayed rubber in the grinding wheel is 45.3%, and the rest of the silicon carbide sand is 0.18KG; the epoxy resin is 0.18KG; the solvent is 0.18KG; the color fiber is 0.007KG;

4. Coconut brown fiber 4KG; resin 4KG (solid content 50%); coir fiber 2.4KG;

Rubber 7.5KG;

In summary, the polishing and grinding composite material is a product of the combination of functionalized fibers and high-performance auxiliary materials. It has the characteristics of energy saving, environmental protection, high efficiency and high quality. It is a new generation of existing industrial sandpaper and polishing materials. Develop application space.

At present, there are only a few Taiwan-funded enterprises that can produce in China. From fiber raw materials to chemical formulas are the subject of research and development.