Installation and adjustment of screen printing machine

I. Installation of screen printing machine

The installation of screen printing machine is an important link to ensure the normal operation of the printing machine. The installation state will affect the operation and use of screen printing machine, and have an important impact on the quality and accuracy of printing machine.

(1) Preparation before installation

Before the screen printing machine is installed, the environment and installation position should be well prepared.That is, before the screen printing machine installation, to prepare a good printing environment, printing environment mainly includes the temperature, humidity, cleanliness and noise requirements.Temperature will affect the ink mobility, humidity will affect the paper deformation and electrostatic generation, cleanliness directly affects the quality of printing.

(2) Understand the installation requirements of screen printing machine

Before screen printing machine installation, you should first read the screen printing machine instructions, detailed understanding of the machine’s structural performance and installation requirements.The installation personnel shall be clear and clear about the installation work to ensure the installation work is carried out in an orderly manner.

(3) Determine the layout of screen printing machine

The layout of screen printing machine directly affects the convenience of printing machine operation. The layout of printing machine should consider the convenience of printing machine operation and space utilization.Consideration should be given to leaving room for operators.A space of 1m above the screen press is sufficient for lighting and operating space on the press.

(4) preparation of foundations

The main function of the foundation is to support the screen press and not allow any distortion where it comes into contact with the screen press.The foundation construction should be carried out according to the requirements and regulations of the machine foundation drawing in the manual. Pay attention to the level of the foundation surface. If the contact surface between the foundation and the printing press support is uneven, it will bring difficulties to the level of the printing platform.

(v) Installation steps and precautions

After the preparation is done, the machine is installed.The screen printing machine is generally installed in the following steps.

1. Split open a case

When unpacking, check and accept the main body, accessories and tools of each box according to the technical data. If any defect is found, contact the transportation unit or the manufacturer in time.Parts and tools should be carefully preserved to prevent loss.

2. Install the host

According to the instructions, put the parts of the screen printing machine in fixed position on the specified ground for installation.

3. Calibrate screen printing table level

Calibration of screen printing table is a key step in the installation of a printing machine. The printing table is in a horizontal state to keep the printing machine working smoothly and the quality of printing products is not damaged.When looking for water, put the level on the printing table to check whether it is level.During inspection, the base of the level and the parts used to check the level should be kept strictly clean, otherwise measurement errors will be caused. These parts had better be repeatedly swabbed with gasoline or warm water.

4. Network version installation

In the installation of screen plate, mainly to determine the position of the substrate, that is, relative to the substrate level around, around and up and down the position of the relationship.There are two ways to determine the horizontal position of the screen when installing the plate. One is to fix the printing table and move the position of the plate towards XY direction with fine-tuning.The second is to determine the screen plate with the substrate between the upper and lower distance.Screen plate and printing (substrate) between the distance, also known as screen distance, screen distance or screen gap.

Adjusting screen spacing is an important part of screen plate and printing table installation. Before printing, the gap between screen plate and substrate (printing table) must be adjusted to meet the printing requirements.

Adjust the clearance manual printing, net frame of the clip on the clamp frame device, choosing a – set the thickness of the pad pad in net box and the box bottom, will screen frame in a horizontal position, then use plug gauge CeLiangWang box bottom and the space between the printing machine, with different thickness of cushion block to adjust the size of the gap, until the gap to meet the requirements of the printing.After the clearance value is adjusted properly, the pad of corresponding thickness is fixed on the printing table to control the clearance size.

It is important to adjust the gap between the surface of the substrate and the surface of the plate so as to maintain a proper gap during printing.

If not properly adjusted, no matter how good the subsequent operation, you will not get the ideal print.When printing, the plate and the substrate surface only contact when the scraping board action, the scraping board will leave after passing.If the clearance is too small, it is easy to produce adhesive version, paste version of the fault phenomenon;If the gap is too large, screen will be due to excessive expansion and relaxation, so that the image size of the printed matter is larger than the screen image size, serious will damage the screen, if the screen is a lack of elasticity of the stainless steel screen, due to its elasticity is very small, the layout and substrate surface contact, can not be printed at all.

To adjust the gap of mechanical printing, the screen frame should be installed on the clamping fixture, so that the screen frame is in a relative horizontal position with the printing table, and then the size of the gap is measured with the plug gauge, and the gap is reached by adjusting the bolt to adjust the movement of the screen frame up and down.After the clearance is adjusted, fix the adjusting bolt and print.

Usually, the printing with higher precision requires a clearance value of 1~3mm.For ordinary printed matter, the clearance value can be 2~6mm.For surface printing, the clearance value should be smaller, while for flat printing, the clearance value can be larger.

5. Installation of scraping board

When using the machine for screen printing, to install the ink plate on the fixture, installation of the ink scraping plate at the midpoint, and the screen plate to the center line alignment.Then according to the operation requirements to determine the scraping Angle.When printing thin items, the squeezer applies pressure from above the plate and pushes forward, so when installing the squeezer, test the squeezer pressure.Put two 100pm thick, 50cm wide and 50cm long polyester films between the back of the plate and the substrate, and use the scraper for pressure scraping. Observe the changes of the two films, observe the resistance, and adjust the force at the left and right ends evenly. Then record the pressure of the scraper.

Screen printing using the length of the ink scraper, mainly according to the size of the printed picture and text size and screen size determined, but also consider the hardness of the ink plate material, ink viscosity and other factors.

The basic principle to determine the length of the ink scraper is to be longer than the width of the picture and text screen size, if the length of the ink scraper is less than the width of the screen can not ensure that the whole screen has ink.The scraper is too long to print and is wasteful.- The length of general ink scraper is 2~ 10cm longer than both ends of the picture size.

Second, screen printing press adjustment

After the screen printing machine is installed, adjustment, trial printing and inspection can be carried out according to the technical standard. It can check the installation accuracy of parts, connection relation and the handover relation of paper in the process of transmission.Through debugging, make the assembled printing press in normal working state.The basic process of printing press debugging is as follows.

(I) A complete inspection of the printing press shall be carried out before operation

It is mainly about the installation of screen printing press connectors, positioning parts and anti-loose parts. There is no other foreign matter on the screen printing machine working platform, otherwise the printing will be seriously damaged.

Phase adjustment of the working cycle of the whole machine

According to the cycle phase diagram designed by the manufacturer, strictly check the machine action sequence, and pin or lock well.The order of action is wrong, necessary adjustment should be made, otherwise the machine will lose its function.In general, the phase of the working cycle has been adjusted so that the user does not have to move again.

(iii) Operation and adjustment of screen printing machine

1. Adjustment of parallelism between guide rail, screen plate and working platform

If the three layers are not parallel, the screen printing machine can hardly work, and the guide rail or platform is generally used as the standard for control.The platform and the guide rail should be parallel, the squeegees move along the guide rail, if the two are not parallel, the squeegees will not always contact the platform with a certain pressure, or even clearance, this adjustment has been adjusted before the machine leaves the factory;Screen plate and the platform should be parallel, otherwise the screen distance (screen plate bottom to the printing surface distance) is not consistent, will cause the printing pressure and screen plate deformation is not consistent, therefore, the screen frame itself flatness should be guaranteed, generally by the user according to the needs of specific requirements.

2. Adjust the scraping plate

The adjustment of the scraping fruit plate to the parallelism of the platform, the left and right of the screw can be adjusted respectively: the middle shaft with the top wire can be adjusted to the left and right of the top wire, the essence is to adjust the high and low position of the scraping ink plate.The adjustment amount of the inclination Angle of the scraper is generally 65°~85°, which can be selected according to the needs;The adjustment of printing pressure should be coordinated with the adjustment of screen plate and printing pad distance.In screen printing, the adjustment of printing pressure is actually the adjustment of the high and low position of the scraper.The length of the scraper can not be adjusted. Generally, it is supplied as a set. There are several different lengths for each set.

3. Adjust the scraping speed

Generally, the size of the whole working cycle can be adjusted by the adjusting handle of the CVT device. Each action should be fast and each action should be slow.Therefore, to ensure the same speed of large and small parts, large parts should increase the working cycle time and reduce the production efficiency.Small print to reduce the working cycle time, improve production efficiency.

4. Stroke adjustment

It includes adjustment of stroke size and stroke position.The screen printing machine using crank mechanism and swing rod mechanism can adjust the stroke by adjusting the crank and swing rod radius (R) hole position, and the stroke of R increase can be increased.The screen printing machine with pneumatic mechanism can adjust the stroke by adjusting the position of the stroke switch.Chain – driven screen printing machine stroke can not be adjusted.The stroke position shall be adjusted according to the pattern’s positioning on the platform.The starting position of the stroke should be close to the operator when printing small size prints.

5. Adjust the plate

Plate adjustment refers to the adjustment of printing accuracy between the screen plate and the printed part on a screen printing machine.

High and low adjustment: according to the thickness of the printing plate and the size of the platform.

Front and rear adjustment: the amount of front and rear adjustment is generally no less than 20mm.

Left-right adjustment: the left-right adjustment quantity is generally no less than 20mm.

Horizontal Angle adjustment: the adjustment amount of horizontal Angle is generally no less than 3° for the machine.

The vertical Angle is generally fixed on a machine.

The main purpose of plate adjustment is to improve the printing accuracy, but the printing accuracy not only depends on the plate adjustment, but also depends on many factors.Printing accuracy includes dimensional accuracy (such as line thickness) and positional accuracy.Position accuracy is measured by the amount of dislocation, which cannot be zero, but should be within a permissible range.The accuracy of the plate is related to the operator’s visual error and the position accuracy of the feed.

6. Adjustment of printing pressure and ink

The first thing to do in printing is to adjust the viscosity of the ink, which is fundamentally related to the pressure of the scraper that is to be used.During printing, ink is pressed to the substrate surface by scraping.Ink through the layout, that is, the layout of a variety of mesh, between the ink and wire mesh resistance, the flow of ink.

The same material screen, the more dense mesh, the greater the resistance.The screen made of nylon, polyester and metal monofilament yarn has the same mesh number as the screen made of silk with multiple twisted threads.

In addition, the amount of ink through the scraper and the size of the layout Angle, the smaller the Angle, the greater the force of the scraper, the more easy to flow oil.In addition, the new degree of ink and wire mesh and ink between the resistance, that is, the more the ink stick its resistance is greater,

The more difficult it is for ink to run out.