In the whole process of hand board processing, after selecting the appropriate processing method CNC processing or 3D printing, most hand boards need surface treatment. Meet the requirements of corrosion resistance, wear resistance, decoration or other special functions of the product. There are also dozens of surface treatment technologies for hand board processing. Today, I'd like to introduce some of them to you:
Step 1 Grind
Sandpaper polishing can be carried out by hand or by abrasive belt polishing machine equipment, which is the most commonly used and widely used technology for post-polishing of 3D printing parts. Sandpaper polishing has problems when dealing with relatively small parts, because it relies on manual or mechanical reciprocating motion.
Generally, the products printed by FDM technology have circles of lines, and it only takes 15 minutes to polish and eliminate the lines the size of the remote controller with sandpaper. If the parts have the minimum requirements for precision and durability, avoid over-polishing, and calculate how much material to polish, otherwise over-polishing will deform and scrap the parts.
Step 2: Polishing
On the basis of polishing, flexible polishing tools and abrasive particles or other polishing media are used to modify the surface of the workpiece.
Polishing cannot improve the dimensional accuracy or geometric shape accuracy of the workpiece, but aims at smooth surface or mirror luster, and is sometimes used to eliminate luster. The surface roughness of the polished workpiece can generally reach Ra0.63 ~ 0.01 microns. PMMA transparent workpieces require very high polishing requirements, so the price of PMMA transparent workpieces is relatively expensive.
3. Sand blasting treatment
Sand blasting uses compressed air as power to form a high-speed spray beam to spray the spray onto the surface of the workpiece at high speed, so that it can obtain certain cleanliness and different roughness, improve the mechanical properties of the workpiece surface, increase the adhesion between the workpiece and the paint coating, prolong the durability of the paint film, and is also beneficial to the leveling and decoration of the paint.
The spray medium is usually very small thermoplastic particles that have been finely ground. They are relatively durable and can be sprayed in the range of slight to severe wear.
Because sandblasting treatment is generally carried out in a closed chamber, it has a size limit on the treated object, and the whole process requires holding nozzles by hand, only one at a time, so it cannot be applied on a large scale.
Step 4 Spray
Surface painting is one of the most widely used surface processes. Spraying has the following advantages:
(1) It can cover the surface defects of the formed workpiece.
(2) A variety of colors, different glossiness, different appearance and visual effects and a variety of different hand feels can be obtained through spraying.
(3) Enhance the hardness and scratch resistance of the workpiece surface; Spraying effects include: matte, semi-matte, high gloss, various colors, various textures, etching lines, wire drawing effect, leather effect, elastic hand feeling effect (rubber paint), etc.
5. Silk Screen Printing
Silk screen printing is a kind of printing, which prints the pattern to the place where it is needed. Frame the screen board with a frame, and then the place where the screen is hollowed out is the pattern to be screened. The dye is coated in the screen, and finally the dye is scraped into the hollowed-out pattern with a scraper, and then the screen printing is completed.
Silk screen printing will be used for general product characters or logo. Common products requiring silk screen printing include electrical appliances, toys and daily necessities. Silk screen printing can only be used for flat products, so uneven and curved products cannot be used for silk screen printing.
Advantages of Silk Screen Printing:
A. Low cost and quick effect;
B. Printing suitable for irregular substrate surface. Through ultraviolet curing, it can be cured in 30 minutes.
C. Strong adhesion, good inking property, thick ink layer, strong stereoscopic impression and good color fineness.
D. The printing object materials are extensive and the printing format is large.
6. Steam smoothing
The 3D printing parts are impregnated in a steam tank with liquid reaching boiling point at the bottom. Steam rises to melt a layer of about 2 microns on the surface of the part, making it smooth and shiny in a few seconds.
Steam smoothing technology is widely used in consumer electronics, prototype and medical applications. This method has little influence on the accuracy, and its disadvantage is that it has size limitation, and its effect on products printed with high heat-resistant materials is not very good.
There are tens of millions of surface treatment methods. Ultimately, it depends on what kind of effect customers want. However, no matter which treatment methods, they will present customers with excellent quality, high cost performance and excellent service, which is the final direction.