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There are many different printing processes on silicone products. silicone silk screen printing, silicone printing, silicone color printing, silicone transfer printing, silicone film printing.

 

Silicone silkscreen printing

swim caps print logo

The silkscreen is the first printing method. Screen printing requires a logo screen set. Generally, the silk screen printing ink will be thicker and brighter, and the printed pattern has a strong dimensional sense. Silkscreen printing can also print thin lines and is also suitable for large-area printing. The disadvantage is that it is low efficiency as by hand printing and only can up to print 5colors. Silkscreen can only print one color at a time, bake it. Then fix another logo screen set to print the second color.

 

Silicone pad printing

pad printing

It is printed by machine with a metal plate. The plate is flat, with the image chemically imprinted. The silicone pad is pressed onto the ink, picking up the image. And then the silicone pad is pressed onto the substrate, transferring the image on the silicone product.

The advantage of pad printing is that the printing speed is fast, and you can print several colors at the same time. Pad printing can be used on a variety of substrates, particularly oddly shaped objects that are difficult to screen print. The disadvantage is that the ink is slightly thinner than the silkscreen, not too bright.

 

Silicone color printing

CMYK printing

color printing is also called digital printing, CMYK printing. The technique used to print full-color images. The silicone ink and the silica gel itself are chemically reacted with each other, so the based product should be white. Otherwise, the logo will be discolored. If the based products in different colors, it is better to print with white ink by silkscreen printing or pad printing first, then do the CMYK printing. However, because there is dust in the printing process, when there is color printing, there will be small dust particles on the surface.

 

Silicone heat transfer printing

silicone bib

Your custom logo is printed on transfer label or film first, and then ink is thermally transferred from the label to the silicone products using heat by press machine. It can print several color logo. But the logo screen is expensive.

 

Silicone water transfer printing

water transfer printing

Firstly put the printed water-soluble film on the surface of the water. Immerse the silicone products into the water, the upward pressure of the water causes the ink to wrap and adhere to the item. Then removed the products from the water. It can be applied to all types of substrates with full colors printing.

 

Silicone film printing

kid swim caps

Cover the film on the silicone while compressing the product, without secondary processing and printing. Washable, folding, scratch-resistant grade A, dry-wearing and wet-resistant grinding A grade, excellent color printing pattern, clear and vivid color printing pattern, environmental protection

 

Ukong can do the above all kind of silicone printing. We carefully evaluated all methods and help you choose the right way to print your silicone products.

TPE over-molding widely used in the thermoplastic elastomer industry. In recent years, with the rise of liquid silicone applications and the excellent properties of liquid silicone rubber materials, TPE over-molding products are gradually being replaced by liquid silicone rubber. The liquid silicone rubber has excellent comprehensive performance. LSR has high-temperature resistance than thermoplastics, soft-touch, high quality of materials meet with the medical-grade requirements. It is the best soft material for over-molding and injection molding and two-color injection molding.

Silicone over-molding is a process that is used to cover, bond, or encapsulate an existing part with silicone material.

Liquid silicone rubber overmolding silicone overmolding

 

The main advantages of liquid silicone over-molding

The liquid silicone rubber(LSR) material has excellent slip resistance and soft elastic touch, which can improve the touch feeling of the product and enhance the grip.

liquid silicone rubber has different hardness range Shore 10-90A according to the physical properties of the product, as well as suitable physical properties (such as abrasion resistance, adhesion, melt index, etc.). A variety of possible material application options are available for different products.

Liquid silicone rubber is an environmentally friendly raw material. It does not contain phthalates, halogens, and does not include 38 SVHC substances of REACH. It meets the environmental testing standards of ROHS, REACH, NP, EN71, and PAHS, and can fully meet the environmental protection requirements.

 

Liquid silicone rubber over-molding processing technology

Silicone rubber over-mold injection molding process involves two steps wherein a completed plastic or metal entity is placed into the mold site of an LSR mold, after which the LSR is over-molded directly onto the part.

The injection molding temperature is different depending on the hard material. The commonly plastic substrate is PC or PA, and aluminum alloy can also be over-molded by liquid silicone rubber.

 

Common problems and solutions for liquid silicone rubber over-molding processing

1) Lack of silicone – the product is trapped air, or the silicone is not enough.

2) blunt, overflow edge – increase the clamping force; reduce the injection pressure.

3) Poor viscosity – choose the right adhesive. Check the plastic or metal substrate is clean.

4) out of shape during Injection molding – lowering the molding temperature; using a high-temperature resistant substrate.

 

Ukong is a liquid silicone product OEM/ODM manufacturer. We are committed to the development of new processes for liquid silicone (LSR) products and custom products. We have advanced molding techniques such as the high speed of injection molding, short vulcanization time, automatic, self-removing, and no burrs.

Our products including the liquid silicone rubber baby care, medical liquid silicone products, mobile phone 3C waterproof accessories, automotive electronic accessories, liquid silicone kitchen products, industrial sealed liquid silicone Products, etc. and has rich experience in the liquid silicone rubber over-molding parts. (liquid silicone rubber to plastic, liquid silicone rubber to metals, liquid silicone rubber to glass or ceramic, silicone two-color products)

 

What is the difference between liquid silicone rubber(LSR) and solid silicone rubber?

Liquid Silicone Rubber is Liquid, Solid silicone rubber is solid and no fluidity. The finished Liquid Silicone Rubber and solid silicone rubber are not easy to distinguish. Liquid silicone rubber finished products has high transparency and odorless with injection feeding mouth, While the finished products of the solid silicone rubber have low transparent.

 

Solid Silicone Rubber

Silicone Rubber

Solid silicone rubber can be made into all kinds of silicone products after vulcanization. Comparing with the injection molding process, the most advantageous of compression molding is the lower cost. The solid silicone molds are cheaper, and the raw materials are also less expensive. Processing is highly variable, so that, a wide range of different parts can be made with a few basic silicone grades.

But the disadvantage is that the manual operation, the self-demolition mold line has no liquid perfection, and the most softness of the product only reaches about 20 degrees.

How to store the Solid Silicone Rubber

  •  Store in closed containers in cool rooms at 0- 30 °C
  • Do not expose to direct sunlight
  • Keep separate from organic rubber and crosslinker chemicals

 

Liquid Silicone Rubber

Liquid silicone rubber

The liquid silicone is liquid. In the production process, the liquid silicone raw material is injected directly into the mold cavity. The process can be fully automated. It does not need to involve a lot of labor. The product is sealed and processed. Therefore, It produces high-quality parts without secondary finishing, and the processing speed is fast. Injection molding is suitable for complex part geometry. Liquid Silicone Rubber is widely in Medical and Baby Care Products.

The disadvantage is that the cost is high, the mold development cost is expensive, and it is uneconomical for the production of small-batch products!

How to store the Liquid Silicone Rubber

  •  Store in closed containers in cool rooms at 0 – 30 °C
  • Higher average temperatures may shorten the shelf life
  • Do not expose to direct sunlight
  • When opening the container, make sure that no dirt falls onto the surface of the rubber

We manufacture silicone components with solid silicone rubber and liquid silicone rubber. We will assist you in choosing the right economical material for your projects.

 

 

 

Silicone is becoming more and more popular in our daily lives. But what is the difference between food grade silicone and ordinary silicone? Ordinary silicone is for industrial products, Ordinary silicone is odorous and opaque. While food-grade silicone is widely used for products that are in contact with our food.

What is Food Grade Silicone?

Food grade silicone is non-toxic and odorless, environmentally friendly – contains no BPA, Latex, Lead, Phthalates and biodegradable, long-term use and other characteristics. Food grade silicone is platinum cured with high elasticity, high transparency, and high tear strength. It meets with the FDA and other environmental requirements. It is safe to contact with food directly.

Food grade silicone is widely application for baby pacifiers, silicone containers, silicone baby bibs, and baby spoons, etc.

silicone container silicone spoon silicone bib

 

How to distinguish Food grade silicone and Ordinary silicone?

food-grade silicone is better quality and high price than ordinary silicone. Some dishonest manufacturers mix regular silicone in products that are in contact with food. So it is important to know how to distinguish their difference?  Here ukong teaches you a simple way as follows.

  1. Pull

Hold the silicone product by hand, focus on one place, and then pull hard on both sides. Turn White is an ordinary silicone, and no white is the food-grade silicone.

food grade silicone

  1. Smell(Auxiliary method)

If the silicone product pulled white and has a pungent smell, then it can be concluded that it is an ordinary silicone, not food grade. This way is practical and straightforward.

Some food-grade silicone has slightly smell after production, but the odour will disappear after a while.

Food safe silicone is a non-toxic type of silicone that doesn’t contain any chemical fillers or byproducts, making it safe for use with food. All the baby bibs, baby spoons, food containers, and some other baby products are made from only 100% food grade silicone which is good quality.

Printed Silicone swim caps are best for schools, clubs, colleges, and special events. We custom swimming caps by the screen printing process up to five colors.

Screen printing is a process of pushing ink through a mesh screen in its current state and can pass through this entire screen, so we need to mask off the areas where we don’t want the ink to go through.

silk screen printing

If you have areas that are mistakes or stuff you don’t want to print yet, you can use some tape to cover them up. Use painter’s tape and not duct tape — the duct tape will rip off the emulsion.

Printed swim caps

Now fix your screen set(one screen for each color) line up center and screw in. Layout the silicone caps on a flat surface.

Pour a small amount of silicone ink(Silicone Ink with perfect viscosity and is very easy to work with, and has excellent opacity)horizontally across the top of the screen. Take your squeegee and make one smooth movement down the screen, exerting strong pressure. To do it evenly, it’s best to find some old swim cap to practice on before you try, and then use your new swimming hat for mass printing.

Lift the screen up, pull the swim caps out (Be careful removing the cap as ink is still wet), and you’re done. To make sure the logo sticks on the swim hats for a long time, put caps in the oven on 180 degrees for a few minutes.

swim caps print logo

Screen printing ink dries too fast, so as soon as you’re done printing swim caps, wash the ink off the screen so you can use it again in the future.  And remember to store the rest ink in the fridge for future printing.

You can customize your swimming hats with your logo printed on both sides. Ukong manufacture plain silicone swim cap, wrinkle-free swim caps, Long hair swim caps and Dome caps with any Pantone colors. We offer the best quality silicone swim caps and printing with a quick turnaround.

 

 

 

 

What is Liquid Silicone Rubber(LSR)?

Silicone rubber is composite materials, such as RTV Silicone (Room-Temperature-Vulcanizing silicone), the high temperature vulcanized silicone rubber (HTV), High Consistency Rubber(HCR) and Liquid Silicone Rubber(LSR).

Properties of liquid silicone rubber(LSR)

1.High temp resistance

The outstanding property of matter in the condition of high temperature(over 200ºC)for a long time, endure short time exposure up to 350ºC

2.Low temp resistance

Outstanding flexibility in the condition of low temperature(-70ºC). possible to use low-temperature material in the condition of ultralow temperature(under-100ºC)

3.Low compression set

Possible to use application for such as seal ring and gasket due to outstanding compressed permanent strain(strong at shrink and distortion by compress)

4.Chemical resistance

Outstanding oil resistance, solvent resistance, and chemical resistance. Aniline, Alcohol or Alkali cannot be invaded.

5.Electric property

Having hydrophobic for water and excellent electric insulation. No decline of performance by exposure to water.

 

LSR injection molding advantage

Complex geometries. Provide excellent expressivity of ultra-thin and complicated shape thanks to the low viscosity of LSR.

Automation. Implement automation of the entire process from Dosing to De-molding in contrast with other labor-intensive rubber injection.

Improved safety. Build a safe production area by an unmanned automation system.

Fast cycle. Improve productivity with innovative cycle time by ‘sec.’ unit compared to ‘min.’ unit cycle time of compression and transfer molding

Material preparation. Prevent contamination and faulty mix of material and save time and labor by eliminating the preparation processes like mixing material.

 

Liquid Silicone Rubber(LSR) application.

Automatic

liquid silicone rubber automatic

Wide Applicable Temperature Range: -50~200ºC (-58 ~392ºF)

Maintain of performance required as automotive part under harsh environment.

Stable physical property, Insulation, Weatherability Permanent compression ratio under the wide temperature range

Flexible joint movement and excellent sealing performance.

Silicone reduces noise by creaking, protect and improve the appearance of exterior parts and keep interior parts robustly.

 

LED

LED is a lighting part made by a compound semiconductor which lights with an electric current.

LSR is applied for encapsulants which protect chip & wire from humidity and external shock. LED package of infrared and visible was used with epoxy encapsulants, silicone encapsulants applied for white and high brightness LED package required for excellent heat, light, yellowing-resisting property.

Why the applicant LSR?

Prevention of light output decrease. Improvement of quality of high performance LED extension of lift time.

Elastomer series. Easy filling for complex shaped parts cracks prevention against stress.

Thermal resistance up to 200ºC. High bright white & blue LED prevents yellowing by UV.

liquid silicone rubber led

 

 Medical 

liquid silicone rubber for medical

Excellent heat-resisting property. Easy sterilization and autoclave available, no acceleration of bacterial multiplication.

Flexible Silicone Material. No harmful to the patient because it does not contain Phthalate and fabricated additives.

No skin trouble and allergy compared to other lubber products because it is a dwelling type. Widely used in the medical industry like a urethral catheter, especially an oxygen mask, diving equipment.

 

Mobile

How about “Sealing”?

Ultra-low compression set. Achievement of 15% permanent compression ratio without curing after 22hours at 175ºC.

Wide Range of Hardness. Possible set up a wide range of hardness and achieve the optimized sealing performance.

Excellent media resistance. Superior mass resistibility and strong for corrosion and chemical parts.

 

How about “Lighting”?

94% Transmission. Approximately 94% uniform transmission over the wide range of visible and invisible light.

<1% Haze. Hazy degree less than 1% after passing through the lens and ensure clarity.

Abbe number. In physics and optics. Abbe number is a measure of the material’s dispersion in relation to the refractive index. The higher abbe number means less light scattering and chromatic aberration. As much more clear reflection.

Durability. High-temperature resistance even above 150ºC. UV light resistance. Micro-crack resistance.

Design Freedom. LSR minimizes stress on complex microstructures based on high flowability. Direct gating through cool runner is available to product required for high tolerance.

 

LSR application examples

Automotive

Wire seal. It could meet the performance and quality required as the automotive part in a wide temperature range from -50~200ºC(-58~392ºF). It makes joint flexible movement and excellent sealing such as O-ring, Wire seal, Gasket, etc.

Babycare

Pacifier. Excellent heat resistance makes hot water disinfection possible. Harmless to humans without bisphenol-A soft touch like mother’s makes baby snug.

LED Packaging

Led lens. Excellent thermal, light and yellowing resistance. Suitable for high luminance LED applied to the lighting. Automotive, mobile, monitor, TV, Display.

Kitchen Appliances

High thermal and fouling resistance.Ideal for home applications because of harmless to humans.

Industrial

Mask. Soft-touch brings excellent wearing sensation. Suitable in a harsh working environment like welding, painting and dealing chemicals without transformation.

Medical

Menstrual cup. Environmentally friendly material medical grade silicone. No detection of endocrine-disrupting chemicals and chemical substances.

Compression Molding

Rubber Compression molding

Compression molding is one form of molded silicone rubber parts. Compressing preformed silicone rubber in a mold with a press during the compression process, Silicone rubber is forced into the mold cavity to form the final product during this process, any excess rubber is pushed into the flash and trim gate allowing easy cleanup once the rubber is set.

Compression molding works best for medium hardness compounds in low volume production. Silicone rubber can be difficult to insert into more complex mold designs. And Soft and Hard silicone rubber compounds don’t do well in the compression molding process.

But Silicone rubber compression molding offers advantages over other methods

  • Cost-effective Tooling
  • Maximized cavity count
  • The short set-up time that saves on short production runs
  • Economical process for medium precision
  • the least amount of waste in comparison to other molded rubber processes. 

Compression molding can be a cost-effective solution when:

  • Having silicone rubber industries manufacture the Tooling.
  • the cross-section of the part is very large and requires a long cure time.

Compression molding is used for anything from simple silicone rubber o ring to the most complex silicone parts.

If compression molding isn’t the best fit for your project, Ukong can offer a variety of other molded silicone rubber products through injection or transfer molding.

 

Injection Molding

Liquid silicone injection molding

Injection molding process involves rapidly injecting an exact amount of Silicone rubber from a tube or cylinder into a closed heated mold, the injection press closes the heated mold and applies pressure to keep the mold closed during the injection and curing cycles, the screw then injects the silicone rubber through the nozzle into the mold. the silicon rubber travels through the mold via a system of runners and sprues and finally enters the mold cavities through a gate, it then fills and packs the cavities to form the desired part rubber.

Injection molding offers economical advantages including:

  • short molding cycle
  • Lower unit cost
  • high dimensional tolerances
  • An absence of flash
  • little scrap or waste.

If you’re interested in what Ukong can do for your company email us at sales@ukongtech.com

 

Transfer Molding

Rubber transfer molding

Transfer molding combines the advantages of injection molding with the ease of compression molding. the process of transfer molding involves placing a rubber and a chamber at the top of the mold and then pushing through sprues into a heated mold.

Transfer molding offers several advantages over other methods,

  • shorter production cycles
  • maintains close dimensional tolerances than compression molding
  • provides uniformity to the molded products
  • fast mode setup.

 

 

The Shore Durometer A Scale is an industry-standard for measuring flexible rubber materials, and this is really important in choosing the right mold material for a particular job or in the case of choosing a casting material that might be a flexible casting material.

Durometer

To get started we need to first understand what is durometer or what the shore A durometer is. The A durometer is both the measurement and the gauge used to measure soft elastomer and what this is a gauge that has a little pin that sticks out at the bottom, and when that pin is pushed in flush with the base of the gauge that’s what gives you the reading on a given flexible material, so depending on how hard how far that pin pushed into the base is determines the hardness or softness of a material. The Shore D Scale measures the hardness of hard rubbers and hard plastics.

Below is a table of shore A hardness scales.

durometer scale

The A scale measures from a zero all the way up to a ninety-five, this is the most common scale for mold making materials. Most flexible rubber materials that you’ll be used for mold making or casting will be found somewhere on the Shore A scale. the low end of the scale a 0 or a 10 is going to be very soft, a high number will be very hard. In fact, the A scale a low number is going to feel very soft almost like human skin, a hard number would feel almost like hard plastic. Most of the materials we use for molding and casting are the lower end of the scale all the way up to the medium. A zero would be about like warm chewing gum, a 10 like human skin, a 50 to 60 would be about like a car tire and a roller skate wheel or a hard hat is going to measure around a 95. 

What materials and durometer can be compression and injection molded? How do you determine what durometer of material to use?

Please remember that the durometer selected will be based on the requirements of your project.

UKONG can help you to choose the material shore hardness for your next silicone project.

 

 

kids swim cap

Putting on swim caps can be painful if not done carefully! And you wouldn’t want to cause damage to the fragile hairline, so here are our tips.

Protect your little one’s hair by using a swim cap. Fitting the cap need not be difficult. Tie long hair back, start with your little one facing away from you. Place hands in the cap and stretch out. lower over their forehead first, slide hands back and down their scalp, make sure the ears tucked away. A child over 3 can help by holding the front of the cap, slide your fingers underneath to tuck loose hair in and make it comfortable. Now they are set to enjoy the water!

When it comes to taking the swim cap off, peel back from the forehead and slide off their back head.

suction plate for baby

Our silicone baby plate is awesomely gripping and helps steady where they should be. These are top tips to show you how to make sure your short plates and bowls don’t budge.

Tip 1. Use a flat smooth surface on maximum suction.

Tip 2. Make sure the surface you’re going to use your suction tableware on is clean and dry.

Tip 3. The maximum suction the silicone plate press down on the center of the plate with a fork or spoon. This is to remove any trapped air underneath to help ensure a complete seal for added suction for maximum suction, avoid using baby wipes on your surface as this can leave a residue that can affect the suction.

Tip 4. Please check that your silicone tableware doesn’t budge, add your little ones food and watch them enjoy controlling their mealtime.

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