Etching-sign-process

A. Surface protection

1. Apply corrosion-resistant photosensitive ink
First choose 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, be sure to carefully stick and press with your hand, so that no air bubbles are left between the scotch tape and the screen, so that they can fully contact and apply. The photosensitive ink will not be applied to the outside of the stainless steel plate. The part where there is no 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 better to make the screen tension large and the screen spacing small, so that it can bounce up in time after printing the ink.
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 to 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, smooth, and clean surface on the slope.
Put an appropriate amount of photosensitive ink on the yarn surface of the screen to form a strip, and then 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 and take it out, taking care 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 give up. Otherwise, the ink is too thick.
In the warm water of about 30 degrees, add an appropriate amount of weakly alkaline sodium carbonate for industrial use, 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 stainless steel surface. Then wipe off the photosensitive ink thoroughly with a clean cloth, rinse with water, and blow dry with a hair dryer, and 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, set the hair dryer to the cold wind position to cool the stainless steel plate, or let it cool naturally.
B. Exposure
Next, go to kR-B1 single-sided vacuum exposure machine for exposure.
Turn on the power first, the ammeter on the control panel shows 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, then put the stainless steel plate on top and the film 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 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 compress the film. This can ensure the sharpness during 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 to count, and the ultraviolet light in the kR-B1 single-sided vacuum exposure machine will pass through the transparent part of the film to treat the photosensitive ink. The exposure. After 45 seconds, the shutter closes automatically, the exposure ends, and the time relay is automatically cleared.
Turn off 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, let the lamp in the exposure machine cool down, and then turn off the main power supply)
C. Development
Add sodium carbonate in 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 a 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 hair dryer.
D. 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 for repair. If the repair is not good, it can only be returned to the previous process and reworked.
E. Hard film
Put the repaired stainless steel plate into an oven, and set the oven temperature to 88 degrees, which 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, which is called hard film. After 10 to 15 minutes, take it out and blow it cold, or let it cool down naturally.
Paste the anti-corrosion protective film on the reverse side of the stainless steel plate of the hard film, so that the reverse side will not be etched and ensure its flatness.
F. 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 suitable Baume concentration is between 38 and 40 degrees.
The method of measuring the concentration is: 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.
If the Baume concentration is 42 degrees, and 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 perform 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 scouring 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 send it into the machine. Pressing 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 ferric ions in the solution quickly oxidize the stainless steel plate, and the stainless steel plate is etched down.
The length of the scouring time determines the depth of the 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 sample engraved stainless steel plate 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. Official etching begins.
4. Formal etching
Put the two stainless steel plates with the solid film and the anti-corrosion protective film on the reverse side at the appropriate 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, check carefully, and 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 in another container filled with clean water, swing a few times to wash the surface, then tear off the anti-corrosion protective film on the back 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 at a ratio of about 1:10 and 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.