There are many types of metal signs and a wide range of applications. Its production process can not only make various styles of signs but also make some exquisite crafts.
1. Preliminary preparation
(1) Design
The design of the sign is the basis of the production of the sign, and the drawing designed by the designer is required to be not only beautiful but also suitable for the production of the subsequent process.
1. Determine the size
Open the CorelDraw drawing software, and draw the outermost outline of the sign with a rectangular tool according to the size required by the customer. Set the length to 184 mm and width to 133 mm. Use the same method to draw another one, enter the appropriate size, adjust the position, and drag the pre-selected decorative lace to the appropriate position in the rectangular box.
2. Choose the shading
Shading is widely used in signs. We choose two kinds of shading, one is laser shading and the other is sand shading. If the pattern of the shading is too large, you can drag the shading to an appropriate position on the screen first, and then delete the extra parts around it.
3. Determine the content
The content of the sign is relatively simple. Put the environmental protection sign in the upper left corner, adjust the size, and then enter the text. The font should be solemn, clear and beautiful, accurate, and easy to recognize. After the layout is completed, check the overall effect. This golden sign with laser shading It’s done.
Just replace the laser shading with sand shading, and it will become a silver sign with sand shading.
(2) Film production
Film films are generally sent to professional film companies, who use laser printing, exposure, development, and fixing processes to obtain them. What we have to do is to take the film back and check it carefully to see if it is consistent with the original. In addition, the film is clean and thorough, and the edges of the lines are very clear.
(3) Cutting
1. Select the plate
The metal plates used to make signs include copper plates, stainless steel plates, titanium plates, etc. Each type of metal plate has different characteristics. You can choose the right plate according to the different styles of the sign. Stainless steel has the advantage of being resistant to corrosion and is a commonly used plate for making metal signs. Now we have chosen a thickness of 0.3 mm.
2. tailoring and trimming
According to the designed size, put a few millimeters margin on each side of the selected stainless steel plate, mark points, and cut it. The cut stainless steel plate often has burrs on the four sides, and it must be filed off with a file. , After filing, touch it with your hand, the edge is smooth, it’s fine.
3. remove oil stains
After the stainless steel plate is soaked in clean water, put some detergent on the surface, wipe the oil stains on the surface of the stainless steel plate with a clean cloth three to four times, and then rinse with clean water to clean the surface of the stainless steel plate. It will affect the smooth progress of subsequent procedures.
4. Blow-dry
Use a hairdryer to dry the remaining water droplets on the surface of the cleaned stainless steel plate without leaving water stains.
2. Etching
The production of stainless steel plate signs is mainly done by etching. Its etching principle is:
This represents the thickness of the stainless steel plate. We first evenly coat a layer of corrosion-resistant photosensitive ink on its surface, put a film negative on it, expose it with ultraviolet light, and pass through the ultraviolet light on the transparent part of the film negative It chemically reacts with the photosensitive ink to form a weak alkali resistant coating, while the photosensitive ink under the black part of the film is not resistant to weak alkali. Take the film negative and soak the stainless steel plate in a weak alkaline sodium carbonate solution. The coating of the weak alkaline part will react chemically with the sodium carbonate solution and fall off, and the metal in these places will be exposed. The stainless steel plate The pattern will appear on the top. Paste a layer of anti-corrosion protective film on its reverse side, put it in the etching machine, wash the exposed surface of the stainless steel plate with ferric chloride solution, the ferric ions in the ferric chloride solution will quickly oxidize and etch This part of the stainless steel plate, we can clearly see with macro shooting, the part of the stainless steel plate is etched down.
Below we introduce the specific operation method of this process step by step:
(1) Surface protection
1.Apply corrosion-resistant photosensitive ink
First, select a 200 mesh screen. The screen version must be extremely clean and of moderate size. Fix it firmly on the professional manual screen printing platform shelf, put the stainless steel plate in the center of the screen plate, keep the edge of the stainless steel plate and the corresponding inner frame of the screen plate at a distance of about 6 cm, too Neither near nor too far is inappropriate. After placing it in the proper position, use scotch tape to stick it around. When sticking, you must carefully stick with your hand while pressing, so that no air bubbles will be left between the scotch tape and the screen, so that they can fully contact. The photosensitive ink will not be applied to the outside of the stainless steel plate. The part without the transparent tape in the middle is exactly the same as the size of the stainless steel plate so that the position will be accurate when the corrosion-resistant photosensitive ink is applied. After everything is glued, clean the surface again to keep the screen surface clean.
We choose a 1 cm thick pad and place it behind the screen plate and the shelf panel of the screen printing platform. The distance between them is the net distance. Generally, it is best to make the screen tension large and the screen spacing small, so that it can bounce up in time after the ink is scraped.
Before using the corrosion-resistant photosensitive ink, adjust the thinness and consistency. In winter, the ink is easy to solidify. You can put it in the oven for a while. The temperature of the oven is set at 88 degrees, let it be automatically controlled, take it out after 5 minutes, stir well, there are no bubbles, like this before it can be used.
Prepare a rubber scraper with an elastic, flat, and clean inclined surface.
Put an appropriate amount of photosensitive ink on the yarn surface of the screen to form a strip, and you can start scraping with a scraper. When scraping, use the right force and the right speed. After scraping 1 or 2 times, Open the screen, if the photosensitive ink printed on the stainless steel plate is very uniform in thickness, you can hold it on the reverse side with your hand, take it out, and be careful not to stain the side coated with the photosensitive ink.
It should be noted that this is often the case. After scraping twice, the effect is still not good, so you have to give up. Otherwise, the ink is too thick.
In the warm water of about 30 degrees, add a proper amount of industrial weakly alkaline sodium carbonate, the ratio is about 20:1. After stirring, put the stainless steel plate that is not evenly coated with the photosensitive ink, and the coating will soon be separated from the surface of the stainless steel. Then wipe off the photosensitive ink thoroughly with a clean cloth, rinse with clean water, and blow-dry with a hairdryer, then you can reprint.
2. Drying
Put the stainless steel plate coated with photosensitive ink in an oven, set the temperature at 88 degrees, and bake for 15 to 20 minutes. After drying, turn the hairdryer to the cold wind position to cool the stainless steel plate, or let it cool naturally.
(2) Exposure
Next, go to kR-B1 single-sided vacuum exposure machine for exposure.
First, turn on the power, the ammeter on the control panel displays 8A-10A, warm up the machine for about 3 minutes, then it can work normally. Align the film and the stainless steel plate and make the two fully contact them, then place the stainless steel plate on top and the film on the bottom, and put them on the worktable of the single-sided vacuum exposure machine steadily.
This air duct is used to suck the vacuum. Put it on one side of the stainless steel plate. Its function is to suck away the air between the rubber in the middle of the cover plate and the stainless steel plate so that the lower surface of the stainless steel plate can press the film. This can ensure the sharpness of the exposure.
Close the lid, lock the hanging buckle, press the vacuum button, and the machine will start vacuuming.
Set the exposure time to 45 seconds and tap the shutter button. At this time, the time relay starts counting, and the ultraviolet light in the kR-B1 single-sided vacuum exposure machine will pass through the transparent part of the film to the photosensitive ink Exposure is in progress. After 45 seconds, the shutter automatically closes, the exposure ends, and the time relay is automatically cleared.
Close the vacuum button, open the locked hanging buckle, and wait until the vacuum meter is basically reset to zero before you can lift the cover and take out the stainless steel plate and film. This is the stainless steel plate after the exposure, and it appears to the naked eye without any change.
It should be noted that after the exposure work is completed, it must be 5 minutes before the lamp in the exposure machine has cooled down before turning off the main power supply.
(3) development
Add sodium carbonate in the warm water of about 30 degrees to prepare a solution at a ratio of 20:1, and stir evenly. Put the exposed stainless steel plate into the weak alkaline sodium carbonate solution. The ink on the part that is not exposed will fall off due to the chemical reaction due to the weak alkali. Use a soft and clean cloth to gently scrub the pattern, and the pattern will be slow. Slowly appeared. After the development is over, rinse the residual sodium carbonate on the stainless steel plate and blow it dry with a hairdryer.
(4) Revised edition
The stainless steel plate after development should be carefully inspected. If there are spots or damages on the coating part of the pattern, you can use a toothpick to dip it in photosensitive ink to repair it. If the repair is not good, it can only be returned to the previous process and reworked.
(5) hard film
Put the repaired stainless steel plate into an oven, and set the oven temperature at 88 degrees. This can increase the bonding force between the coating on the pattern and the surface of the stainless steel, and increase the strength of the surface. This is called a hard film. After 10 to 15 minutes, take it out and blow it to cool, or let it cool down naturally. Paste an anti-corrosion protective film on the reverse side of the stainless steel plate of the strong film, so that the reverse side will not be etched and ensure its flatness.
(6) etching
Next, we will perform etching in the KR-J1 precision swing etching machine
1. Liquid preparation
Used as an etchant is ferric chloride solution. Its Baume concentration is very important in the etching process and directly affects the etching speed. The appropriate concentration of Baume is between 38 and 40 degrees. The method of measuring the concentration is to pour the ferric chloride solution into a slender measuring cup, insert the Baume meter, and the value next to the liquid surface is its Baume concentration. The current Baume concentration is 42 degrees. Some are too thick. We can add water to dilute it, stir it evenly, take a sample and measure it again. If the Baume concentration is too low, you can add a high-concentration ferric chloride solution. After the Baume concentration is properly adjusted, pour it into the box of the etching machine and cover the lid.
2. turn on
The etching machine uses a 380V power supply. Turn on the power switch, the power indicator light is on. Start the acid pump, let the ferric chloride solution circulate in the machine, and observe that the temperature gauge cannot exceed 50 degrees. Press the conveyor belt switch to carry out a test run of the whole machine.
3. Trial
The conveyor belt of this precision swing etching machine can be steplessly adjusted, and the length of the flushing time can be adjusted here. After the etching machine is running normally, first put a stainless steel plate for trial engraving at the material inlet, and the conveyor belt will slowly feed it into the machine. Press the etching switch, the nozzle in the machine starts to spray ferric chloride solution, and its pressure is basically constant. The ferric chloride solution continuously washes the surface of the stainless steel plate, and the trivalent iron ions in the solution rapidly oxidize the stainless steel plate, and the stainless steel plate is etched down. The length of scouring time determines the depth of etching. Tip: If the etching is too deep, increase the speed of the conveyor belt: If the etching is too shallow, reduce the speed of the conveyor belt.
After about 3 minutes, we can get the stainless steel plate for trial engraving at the discharge port, and try to touch the depth of the etching with our hands. If you feel a bit high and low on your fingers, the depth at this time is about 0.1 mm, you can Official etching begins.
4. Formal etching
Put the two stainless steel plates with the strong film and the anti-corrosion protective film on the reverse side at the proper position of the feed inlet, press the etching switch, and the etching machine will begin to etch the stainless steel plate. After 3 minutes, we are in The two stainless steel plates seen at the discharge port, carefully check, like this, the etching effect we require is achieved.
5. fading
Put the etched stainless steel plate into clean water first, and wash off the ferric chloride solution with a clean cloth. Then put it into another container filled with clean water, swing a few times to wash the surface, then tear off the anti-corrosion protective film on the reverse side of the stainless steel plate, and place the two stainless steel plates on the solid sodium hydroxide. In the container, add 70 to 80 degrees hot water in a ratio of about 1:10, swing the container to fully dissolve the sodium hydroxide. We can see that the remaining film on the two stainless steel plates will slowly fade away. Swing until the water temperature is 20 or 30 degrees before you can wipe them with a clean cloth. Then put the stainless steel plate into a bucket filled with clean water for rinsing.
The semi-finished etched sign looks like this. Just let it dry naturally.
3. post-processing
To process semi-finished signs to finished products, post-processing is also indispensable.
This link is mainly electroplating. Electroplating refers to the use of direct current to allow the semi-finished metal to undergo an electrolytic reaction in a solution, thereby evenly attaching a thin layer of other metals or alloys to its surface. Now local governments have stipulated that electroplating can only be carried out by professional electroplating companies. Therefore, for electroplating, we only briefly introduce its process flow.
(1) Electroplating
Before electroplating, drill a small hole with a bench drill in the place reserved for the semi-finished product of the sign, and tie the conductive copper wire through a small section through the small hole, leaving enough length at the other end.
Electroplating generally consists of multiple links, which can be carried out as needed.
4 hours before plating, turn on the main power of the plating tank to preheat.
- Electric degreasing
No matter what the plating is, we must completely remove the oil stains remaining on the surface of the semi-finished product during the previous processing. The effect of electrolysis oil is very good.
We put the semi-finished products of the laser shading label into the degreasing solution in the pool, and tie the copper wire at the upper end to this copper pipe so that the copper wire and the copper pipe are in full contact to ensure good conduction.
Set the temperature to 58 degrees, the time to 300 seconds, and the current to 10 amps.
Now you can see the solution in the pool tumbling constantly, which shows that a chemical reaction is taking place. After 300 seconds have elapsed, the current is automatically cut off, the semi-finished products of the laser shading signs are removed, and they are rinsed in 5 small tanks of distilled water in sequence.
2. nickel plating
Put the semi-finished product with the laser shading after the electrolysis oil is put into the green nickel chloride solution, and the operation is the same as the previous process. Set the temperature to 25 degrees, the time to be 300 seconds, and the current to be 10 amps, and the nickel chloride solution will begin to chemically react with the semi-finished products of the laser shading sign. After 300 seconds, rinse it in 3 small tanks of distilled water in sequence.
3. copper plating The copper plating method is the same as the nickel plating above. The blue solution is copper chloride. At this time, the temperature is 28 degrees, the time is 300 seconds, and the current is 10 amps. After plating, rinse it in 3 small tanks of distilled water in sequence.
4. silver plated
Put the semi-finished product with the laser shading of the copper-plated into the silver nitrate solution, set the temperature to 58 degrees, the time to 300 seconds, and the current to 10 amps. After plating, place it in the 3 small tanks in order. Rinse clean in distilled water.
- Gold-plated
Clamp a conductive clip on the copper wire of the semi-finished product of the laser-shaded sign, and put the semi-finished product of the laser-shaded sign into a solution of potassium cyanide gold. Set the temperature to 52 degrees, the time to 30 seconds, and the current to 5A. Hold the copper wire in your hand and let the silver-plated sign swing back and forth in the solution. Finally, put it out, and rinse them in 2 small tanks of distilled water in order.
Look now, the semi-finished products of the laser shading signs have become golden! At this time, the shading of the laser is also more obvious.
Signs with sand shading only require silver plating. Then it is different from the gilding of the laser shading in the electroplating link, but it is missing a gold-plating link. In the other links, the sequence, temperature, time, current, etc. are all the same, so we will not introduce them separately. The effect after silver plating!
(2) packaging
- Trimming
After the electroplating of the sign, the margin on the semi-finished product must be cut off. Put the semi-finished product of the sign on the appropriate position of the cutting trigger, cover it with a piece of cardboard and then cut it to avoid scratching the electroplating on the surface of the sign.
2. choose a decorative board
The decorative board behind the sign is an indispensable part of placing and installing the sign. It can make the sign more perfect.
We choose these few imitation mahogany decorative boards with no scratches on the surface.
3. sticky board
On the selected decorative board, measure and mark the position where the sign is to be pasted.
Stick two double-sided tapes on the decorative board, squeeze some glass glue on the four corners and the middle, tear off the protective paper on the double-sided tape, stick the stainless steel plate to the decorative board, press firmly, and lay it flat for 5 minutes Above.
4. Safekeeping
Put the completed work in the packaging bag and keep it properly.
4. other types of signs
People often compare the label of a product to a “window to the product.” This vividly shows that users can understand the relevant information of the product through the sign, and explains its importance. Product labels of various specifications are indispensable in machinery manufacturing.
The production process of the product label is exactly the same as before until the etching.
Let’s start from the process of cleaning the ferric chloride solution on the semi-finished product after etching, but without removing the film, and directly entering the coloring process.
The coloring of the product label generally uses the electrophoretic coloring process, and the coloring machine uses colored cathodic electrophoretic paint. We used black this time.
Before coloring, connect the negative pole to the conductive pole plate and connect the positive pole to the gap in the protective film of the semi-finished product to ensure that the semi-finished product is conductive. Then put the semi-finished sign in the black cathodic electrophoretic paint with the conductive clip in your hand, turn on the power, and set the time to 40 seconds. After the time is up, the painter will automatically cut off the power and the color of the sign will be It’s ready. Rinse the excess floating color with water, put it in an oven, set the temperature to 88 degrees, and heat it for 20 minutes to cure the paint film.
Add solid sodium hydroxide to a clean container, put the colorful label on it, add hot water of about 80 degrees in a ratio of 1:10, swing the container, and when the sodium hydroxide solid is fully dissolved, the label The photosensitive film left after the semi-finished product is etched is slowly corroded. After swinging for half a minute, take out the sign and wash away the corrosive liquid remaining on the surface with water.
After the black and white signs are naturally dried, they can be cut to become the window of the product.
I would also like to emphasize that this sign production process can not only be single-sided etching, but also double-sided hollow etching. This is very useful in handicraft production. If we make two identical films, insert a metal plate coated with corrosion-resistant photosensitive ink on both sides in the middle, and expose both sides in the KR-B2 double-sided vacuum exposure machine, and simultaneously up and down in the etching machine. Etching takes a little longer and the metal plate will be carved through. Can make such exquisite crafts.
In short, the production methods of signs are diverse and colorful. As long as we can use our brains and practice more, we believe that the sign manufacturing industry can also make our tomorrow better.
