Stainless steel signs are made from 304 stainless steel, which has good resistance to corrosion by atmospheric and fresh water media, and is decorated with a very high grade aesthetic effect by etching, polishing and brushing.
The main raw material for the chemical corrosion process is ferric chloride. The following is the recipe for the corrosion of stainless steel with ferric chloride: ferric chloride, active agent, water. The formula for ferric chloride should be kept at around 42 BoM, with 0.8-1.2 ml of active agent added per litre of ferric chloride solution. The bottom surface of the stainless steel corroded according to the recipe is flat and smooth, without black passivation film and pockmark-like.
Stainless steel signs are broadly divided into three categories: concave signs, convex signs and signs with a combination of convex and concave letters.
The basic requirements of etched signs: beautiful patterns, clear lines, suitable depth, flat bottom, full colour, even drawings and consistent surface colour.
Characteristics of etched signs: corrosion resistance, good oxidation resistance, weather resistance and solvent resistance.
Features of the shape: strong three-dimensionality, metallic colour retention and clear edge contours.
1. Receive engineering drawings
According to the CDR, AI or cad format engineering drawings provided by the customer, according to the size, colour, thickness, glue and other process requirements to customize, to determine the drawings, we will first free samples and send samples to the customer to determine, the customer to confirm the customized goods.
2. Film production
After placing the order, we need about one morning or afternoon on the computer to make the layout according to the identified drawings. During the layout process, a precise gap of 3mm is left between the edge of the film sheet and each logo in order to ensure that the product produced does not come off when picked up, to maximise the yield of the finished product.
3. Plate processing
Work instructions: The front side of the plate is polished using a 2400 rpm distribution wheel to achieve a mirror finish, then dewaxed, degreased, cleaned and dried for use.
4. Screen printing of photopolymers
Because extremely fine patterns are produced. It is impossible to repair them after development, so it is particularly important to choose a good photopolymer. Our company uses Gao (coates) photographic imaging corrosion-resistant ink, using 200 mesh screen full-page printing, the first printing polished surface, 100 ℃ baking 15 minutes, the second printing the reverse side, then 100 ℃ baking 30 minutes, to be cooled, the surface is not sticky hands, before exposure.
Exposure time: suction plate machine related exposure. Exposure time of 20-100 seconds, the thinner the line, the longer the exposure time, and vice versa, the shorter the exposure time; according to the precision requirements of the workpiece to properly adjust the exposure time, the higher the precision requirements, the exposure time should be appropriately shortened.
Develop with 3-5% sodium carbonate aqueous solution, water temperature at about 50 ℃, after a few seconds of water blistering, gently brush the water solution with a soft brush, and then rinse twice with water to reach completely free of residual glue so far. Wet steel plate can be etched directly, or can be etched after drying.
1. The operator puts the material to be baked into the electric oven through the material rack for baking.
2. The temperature of the electric oven is set at 105±5°C and the time is set at 15±3 minutes.
3. The electric oven is kept dry and clean.
In the industry there are two methods of electrochemical etching and chemical etching. Electrochemical etching is the use of the principle of anodic dissolution, the workpiece to be etched as the anode, under the action of direct current to make the workpiece or part of the workpiece gradually dissolved in the electrolyte, in order to achieve the purpose of etching. Also known as electrolytic etching. Unlike electrochemical etching, chemical etching is a form of etching that uses the principle of redox reaction between the metal and the etching solution. As far as the current level of etching processes is concerned, chemical etching is more widely and popularly used.
Etching can be carried out in two ways.
A, electrolysis method: current 15-50A, voltage 3-5V, electrolyte: 20% ammonium chloride, 20% potassium chloride, 20% sulphuric acid, anode plus titanium plate. During the electrolysis, remove the electrolytic copper floating on the anode in time to ensure the normal passage of current.
B. Ferric chloride method: choose a purer ferric chloride soaked into a 30 boehm solution, flowing corrosion. The same layout can achieve different depths of effect, after reaching the shallow layer requirements, the first time to clean and dry the surface. In the shallow etching has been achieved in the coating (printed matter) on the ordinary etching ink, and then the second etching.
The etched copper plate is placed in a 30:1:0.1 solution of water, sodium hydroxide and potassium cyanide and heated to 70°C to remove the film and remove the light.
1. Upon receipt of the finished plated product, the consignee should record the quantity, name and specification faithfully.
2. Wipe the product clean with the relevant material and do not scratch it.
3. Pay attention to whether the product quality is good or not, if there is any defect it should be returned to the person in charge of the previous process in time, if there is serious defect it should be notified to the person in charge to deal with it, it should not flow into the next process.
4.The coating film must use the specified protective film, check whether the coating film is sticky, off the print, off the glue and other undesirable phenomena, each layer of the coating film must be affixed flat, there must be no bubbles, wrinkles, so as not to lead to bad glue coating.
5.Proper operating techniques must be used when lifting to avoid poor product alignment.
6. Sensitive adhesive must be stuck cleanly and special adhesive film sheets must be stuck flat to avoid deformation and falling off of the product.
7. After all processes are completed, the product name, specification and quantity should be marked according to the product to facilitate the flow of the next process.
11. Offset Printing
1. Check if the machine is running normally before spray painting.
2. Seal the gluing net according to the size of the whole product and check if the gluing net is tight or broken. In particular, no surface defects are allowed in the gluing area.
3. Choose a suitable screen, check that the screen is not damaged and then position the screen.
4、 Painting technique: hold up the squeegee so that it is pulled upwards at an angle of 45°-50° to the screen. Keep the printing direction at both ends of the squeegee consistent with the printing direction when adjusting the position to prevent printing misalignment.
5、 Clean the screen immediately after operation to avoid over-drying of the glue, causing cleaning difficulties and blocking the screen grit, leading to scrapping etc.!
6、 Air drying data: When the temperature is lower than 10℃, use a heating fan to keep the air drying time between 10℃ and 20℃ at room temperature, the air drying time is 110 minutes, at room temperature, the air drying time is 80 minutes, when the temperature is higher than 30℃, the air drying time is 50 minutes. Immediately after the product has dried, put the release paper back in place, taking care not to scrap the product by putting the paper back in place.
7. Clean the machine and maintain the equipment daily.
1、 Place the product and press the button switch, do not put your hand into the machine to avoid pressing your hand when the machine is running.
2. The product should be flat and neat and the four corners should not be cocked to avoid brushing the glue on the product in place.
12. Turning goods
1、 Check that the protective film is free from the print and that it is sticky.
2、 Lay the product flat on the work surface and keep the work surface neat and tidy.
3、 Select the applicable standard protective film to prevent the product from closing and misalignment; otherwise the work will stop or the operation will take longer.
4、 The surface of the product must be clean of glue and any phi, pockmarks, dirt etc. must be removed.
5、 Pay attention to the front and back of the release paper, do not put it upside down, otherwise the product will be scrapped.
6、 After turning the product, mark the name, specification and quantity so that it can go to the next process.
1、 Use the correct technique to operate the straightedge and tool.
2、 Press the ruler against the product to avoid scratching the product or hurting the hands.
3、 Cut the edge neatly to the size required by the customer.
4、 Store the cutter properly and slide it into the cutter slot after use to avoid injury.
5、 The hand position product that needs to be pulled back does not have to be aligned with the sample and cannot be deviated.
1. Employees in the QC inspection process of displacement, letter leakage, pockmarks, batch fronts, etc. are considered as defective products for marking.
15 Packing material
Operating steps: 1.
1. Pack according to customer requirements.
2. Pay attention to the name, specification and quantity of the package, do not package or mix other products.
3. Pack without dirt or impurities in the bag.
4. The data of each package must be uniform and should be clearly marked, with end numbers packed separately.
5. Products without QC inspection can be packed, and only after QC inspection can be packed.
6、 Packaging labels must not be altered at will, with clear and identifiable handwriting and with ROHS labels.
7、 Fill in the report when each product is shipped for tracking.