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3 Production of silicone rubber molds and vacuum injection type polyurethane parts
3.1 Silicone rubber mold making process based on SLA prototype
A silicone rubber mold can be made by using a rapid prototyping original model. The mold has good emulation, strength and extremely low shrinkage, easy demolding, and mold modification is also very convenient. The silicone rubber mold can be used as a mold for a vacuum-type process, and can be used as a mold for precision casting in the middle. The silicone rubber molding process is:
(1) SLA Prototype Surface Treatment SLA prototypes require surface finishes to reduce the surface roughness of the prototype. Only the surface of the prototype is smooth enough to ensure a high surface quality of the silicone rubber mold.
(2) The shape of the cast frame and the fixed prototype are designed according to the geometry of the prototype and the requirements of the silicone mold. Before fixing the prototype, you need to determine the location of the parting surface and the lifting mouth. Once the parting surface and gate are selected and processed, the prototype is fixed in the frame.
(3) The amount of silicone rubber metered, mixed and vacuum defoamed silicone rubber should be accurately measured according to the size of the frame and the density of silicone rubber. The metered silicone rubber is added with an appropriate proportion of the curing agent, stirred uniformly, and vacuum degassed. The defoaming time should be based on the degree of vacuum achieved.
(4) The silicone rubber casting and curing silicone rubber mixture is vacuum defoamed and poured into the frame of the fixed prototype. After the silicone rubber is poured, to ensure that the cavity is filled well, vacuum defoaming is performed again. The purpose of defoaming is to extract the gas incorporated into the silica gel during the casting process and the gas enclosed in the prototype cavity. After defoaming, the silica gel mold can be self-cured or cured. Warm curing can shorten the curing time.
(5) Remove the frame, cut the mold and take out the prototype. When the silicone rubber mold is solidified, the frame can be removed and the sprue bar can be removed. The knife was cut open with reference to the mark of the prototype parting surface, and the prototype was taken out to obtain a silicone rubber mold having a prototype shape cavity.
The process parameters of silicone rubber mold based on SLA prototype were obtained through experiments: the ratio of silicone rubber to curing agent was 10 to 1; the vacuum degree during vacuum defoaming was 85 kPa, and the time was about 5 min; the curing time at room temperature was about The curing time at 50 ° C was about 4 h at 24 h.
3.2 Vacuum injection molding process Silicone rubber mold can be used to make 20-30 pieces of polyurethane parts quickly in vacuum injection molding machine, so that the original products designed and manufactured by the above process can be used for small batch production. It is also possible to carry out trial production of the prototype to analyze and design the market.
The vacuum injection molding process is to cast a two-component polyurethane material into a silicone rubber mold under a vacuum environment, and then solidify to form a product having a silicone rubber mold cavity shape. Before using the vacuum injection molding machine, the silicone rubber mold is assembled and placed in the vacuum chamber. According to the preset parameters, the machine starts to vacuum, remove the gas, and thoroughly mix the two components of the polyurethane in a vacuum environment. The pressure is appropriately reduced, and after a period of stabilization, the combined polyurethane liquid is injected into the silicone rubber mold. The vacuum was released, and the silicone rubber mold was allowed to stand at room temperature for 30 min, and then baked in an oven for 2 to 3 h to completely cure the liquid polyurethane. Using this process, 20 - 30 polyurethane parts can be made in a set of silicone rubber molds. Silicone rubber molds and vacuum injection molded polyurethane parts manufactured by the SLA prototype based on the dragon shape are shown in Fig. 5.
4 Conclusion
Innovative design and rapid market response are key to winning a competitive market. The product design and rapid manufacturing method of this paper combines 3D CAD modeling with rapid prototyping and rapid prototyping to provide a convenient and fast way for new product development. The important feature of this method is based on the feature modeling of digital pictures. The key features in some flat pictures can be used in the design of three-dimensional products, especially suitable for some product features that pay more attention to modeling and not pay attention to precision. The process described in this article can be used in the development of some new products as well as in the modeling of crafts.
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We were founded in Y2015 at Singapore Industry Park, Suzhou, which is half hour`s car ride from Shanghai. In Y2019, we setup our HONGKONG office to support the growing of oversea business. We has established two business units to support different market strategy. Winch is our star product in off-road BU. We provide electric winch various from 2000lbs to 20000lbs, serve the industry for ATV/UTV, Jeep and truck. We also provide hydraulic winch from 10000lbs to 20000lbs, to serve the professional rescue industry. To ensure our winch always has best quality and best cost, we manufacture each key component by ourselves, like motor, gear box, rack, etc. Our manufacturing process covers Aluminum die-casting, punching, machining, CNC, and so on. Our quality department follows ISO 9 0 0 1 to control the process quality and the product quality. We provide our customer OEM/ODM service. The new design will be provided to support the new developed customer and protect the existing customer as well.
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If you need to get something unstuck, lifted, or loaded, an electric winch can save a ton of back-breaking work.
The hardest part may be deciding which one you need.
Winches are commonly available with either a 12V DC or a 110V AC motor.
For fixed operations, such as a marine railway, a 110V winch works well because it can be plugged into an electrical outlet.
For portable applications or use with a vehicle as the anchor, a 12v Winch is the way to go. These units can be hard-wired into a vehicle or simply hooked up to a battery.
The next consideration is capacity-what weight rating should you look for? As a general rule, take the maximum load that you expect to winch and multiply it by 1.5. The weight rating is based on the first wrap of the cable around the drum. With each layer of cable, the pull capacity actually drops, so when in doubt, go larger.
Always stay well to the side of a working winch, and always drape a heavy jacket or tarp over the line. If a cable breaks, the heavy material will help absorb the energy of the taut cable as it snaps back, and reduce the chance of injury.
If a load outweighs your winch rating, remember those high school physics lessons about pulleys and mechanical advantage. You can double the pulling capacity by [doubling" the line. Run it through a Snatch Block attached to the object you`re moving and then back to a fixed object. Twice the capacity, however, equals half the pulling speed.
15000 Lbs Winch,Hydraulic Winch,Truck Hydraulic Winch,Rescue Car Winch
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