Surface Treatment Technology On Plastics

Plastic products has been being a mainstream in the product manufacturing. We can say that plastics can be used in more than eighty percent of the products. For product design, how to use of plastic material is an important challenge, you need to understand all kinds of surface treatment technology, in order to better use in the design and express your creativity and make them true.

Let’s see what surface treatment process can be used for the plastic materials.

1. In-Mold Decoration-IMD

It puts the printed film into the metal mold, and injects the resin used for forming into the metal mold and make them joined with the film. It is a forming method which make a printed patterned film integrated with the resin and solidified into a finished product. IMD includes IML (no stretching, small surface), IMF (high stretching products, 3D), IMR(surface film removed, leaving only ink on the surface).  At present, IML and IMF are collectively referred to as IML.

IML process flow:

IMR process flow:

Technical Features

● Exquisite decorative graphics, logo hidden, resistant to friction or chemical corrosion

● The graphic, logo and color design can be changed at any time without changing the mold

● High printing accuracy, error ±0.05mm for 3d products

● Can provide graphics, logo back light transmittance and high transmittance window effect

● Lifespan of function button can reach more than 1 million times

● Three-dimensional variation can increase the designer's freedom of product design

● Composite forming process achieves seamless effect.

2. Painting

It is a coating method that use spray gun and other spray tools to atomize the paint and spray on the coated workpiece. 

Process flow: injection → primer → drying → finish coating→ drying

Technical Features

● Rich color

● Processing in liquid environment, can realize the surface treatment of complex structure

● Mature process, can be made in mass production

● Unique transparency, high gloss

Disadvantages

● The cost is high, low cost positioning products are not suitable for this process  

● The process is relatively complex, low yield

3. NCVM

NCVM: Non conductive vacuum metallization. NCVM adopts to plate out films such as metal and insulating compound, utilizes each mutually discontinuous characteristic, obtains the effect that FINAL APPEARANCE has metal-like and do not have influence on wireless communication transmission.

Process flow:

Technical Features

● The product is not conductive, can pass a high voltage test of tens of thousands of volts, no

conduction or breakdown  

● The surface of the product has a metallic texture and can realize semi-transparent control  

4. Electroplating

It enables plastics to obtain metallic effect surfaces at higher yield and lower cost.  Similar to PVD. PVD is a physical principle, electroplating is chemical plating, mainly divided into vacuum plating and water plating.

Advantages

● Weight reduction

● Comprehensive cost saving  

● Less processing procedures

● Simulation of metal parts

Disadvantages

● Can not be changed in the process of forming including metal plug-in

● It is much more difficult to mold parts larger than 200 square inches than to cast them  

● There is a danger of fire when electroplated plastics are used for certain household appliances

5. Printing

Plastic printing: It is a process of pad printing by pad printing, screen printing, transfer printing and other methods to print the required pattern on the surface of plastic parts: etch the designed patterns on the printing board, and make the board coated with ink, and then transfer most of the iink to the printed objects through the silicone head.

Screen printing: A major printing process in typography in which the plate is netted and the ink on the plate is removed from the through-hole portion of the plate by the squeegee to the substrate. Usually the screen is made of nylon, poly vinegar, silk or metal mesh.

Transfer printing (water transfer, heat transfer):

Water transfer printing: It is a kind of printing that uses water pressure to hydrolyze the transfer paper/plastic film with color pattern.

Heat transfer printing: It is a technology that prints the pattern or pattern to the heat-resistant adhesive paper, and prints the pattern pattern of the ink layer to the finished material by heating and pressurizing.

6. Laser Engraving

Laser engraving: also known as laser carving or laser marking, is a surface treatment process using optical principles, similar to screen printing pad printing, it can be typed or patterned on the surface of the product by laser engraving.

Technical Features

● Wide range, safe and reliable

● Accurate and meticulous, safe and fast

● Low cost, environmental protection

Types of raw material for plastic laser engraving:

1. Thermoplastics: refers to the plastic that will melt after heating, can flow to the mold after cooling and forming, and will melt again after heating. You can use heating and cooling to make it [reversible change](liquid ←→ solid), which is the so-called physical change, mainly PE, PP, PVC, PS, ABS, PMMA, POM, PC, PA and other common raw materials.

2. Thermosetting plastics: after heating, the molecular structure will be combined into a network, but once combined into a network polymer, even if reheating it will not soften, showing the so-called [non-reversible change], is the change in molecular structure (chemical change) caused by. Some bakelite and amino plastics belong to this category.  

7. Texture

It is a process method that use chemicals such as concentrated sulfuric acid to corrode the inside of the plastic molding mold, forms lines of snake, etching, ploughing and others, plastic surface after molding through a mold has the corresponding lines.

Process flow:

Mold receiving → sandblasting → chemical cleaning (pickling)→ decal → adding asphalt powder → heating → dry paint → chemical corrosion → chemical cleaning → sandblasting → product inspection  

Technical Features

● Improve the visual effect and feel of the product

● Anti-slip

● Increase the surface area, conducive to heat dissipation

● Conducive to demoulding, easy to shape