0 Introduction
All electric wire and cables are common required to be printed with manufacturer’s name, product model and rated power etc continuos information. Generally, the printing effect should complian with the standard of electric cable. Nowadays, main printing method can be divided into 2 types, contact and non-contact type. Among contact type, there are oil wheel printing, color tape printing and hot foil type printing. Non-contact type is inkjet pring and laser type printing. This article is mainly used to describe several methods that widely used overseas, to analyze the advantages and defect and suitable cables. Especially the hot foil printing and laser printing method.
1 Oil Wheel Printing
1.1Advantages and suitable cable
Oil Printing is one method adopting oil print device to print oil on cable’s surface. Mostly used for not printing meters.
Advantages: Printing effect is good and one machine can print in different colors
Disadvantages:1 huge demand on printing wheel 2 oil is expensive consumption, according to different cable material, should choose different oi 3 oil is harmful to human’s health 4 it can’t print dynamic meters 5 printing effect is not very clear, un-intergrity and dirty effect
1.2 Note
Before using this method, you shoud pay attention to following questions:
1 Before buying the wheel, should clarify your requirement on the surface abrasion and hardness to ensure it’s lifetime.
2To protect the oil wheel, we should consider the doctor-bar material, usually we use anti-abrasion PP material
3The oil wheel must be fitted well, It’s tangential surface should be in the central line.
4While choose the oil, pay more attention to it’s quality to ensure printing effece is clear and solid.
5Choose different oil according to different material of the cable. For example the XLPE material, we should choose specialized oil suitable for XLPE material, can not choose PVC material oil. When chooseing oil, should pay attention to itself light, color, attachment, cover. Especially the attachment
6Printing environment temperature and humidity, when humidity is high, and temperature is low. While using plastic con-cave mould to print, due to the fast speed of Solvent Evaporation ( Usually the surface becomes dry within 1 Min ). So to absorb the heat surround causing the water vapor rapid cooling. Make the the surafce of the printing oil surface spray and loose it’s ligh. During rainny days, pay more attention to the environmental temperature and humidity to ensure good effect.
1.3 Improve quality of the oil wheel
To improve the attachment of the printing characters, apply plasma technology into oil wheel printing method. According the specific technical requirement, use plasma technology dealing the surface of cable, the plasma particles strike the surface of the cable material, to let the surface become rough then improving the attachment effect to solve the oil erasing problem. Because the plasma technology improves the plastic improvement technology, the humidity becomes higher. So using this method is simple, operation is eas, speed is fast, and effect is good, also it’s envrionmentally friendly way.
2 Inkjet printer
2.1 Advantages
Inkjet printer method is using inkjet printer to print specialized oil on cable’s surface. It’s widely used cable’s insulation and sheath layer. It has high automation, easy operation. But it’s character is easy to erase according the environmental factors
Advantages: Easy operation, good printing effect, the conent and the character size can be adjusted, print dynamic meters. And can print multi lines of characters.
Disadvantages:1 special oil price is expensive, usually one set inkjet printer oil comsumption price is greater than $2,000 dolloars; 2 One set machine can only print on color; 3 Fast speed small size cable, it’s surface printing effect is not good. While using inkjet printer to print on small size cables, because of the distance of printing head and cable product, the characters will lose part.
Usually, for the small size and indoor cables, it’s suitable to use inkjet printer, because indoor temerature is warm. The character won’t drop due to outdoor environment. As for PVC, PE, LSZH,EPR, CPE and Silicon rubber materials, they all can use this type printing method. Special XLPE material is not suitable because of the stability.
Note:
Inkjet printer is widely used, it’s the most common way of printing mehod, in actual production process, we should pay attention to:
1) Because the cable is keeping moving during production, and it may swing during production, then the characters size is not fixed. Characters will transform and not clear. So we need to add the fixed device at inkjet head. Set the cable running stablely to meet the requriements of distance between of inkjet head and cables. Effect will be better.
2) Inkjet printer accessories price is high, usually the factory’s techncian can do simple maintenance, but when it occurs severe problems, it only wait manufacturef of the printer to fix the problems, if it takes long time to fix the problem, it will influence the delivery date of the cable product. So while buying inkjet printer, it’s prior to choose manufacturer that can offer instant after sales service. If possible, there’s one person to be responsible for the inkjet printer.
3) Inkjet printer adopts oil and diluent which are volatile and acid-corrosion type liquid. It means during production there’s strong sensitive smell. This is harmful to people’s health. The operators shoud have protection sheilds
In addition, to improve the attachment of the printing characters, can also use plasma technology into inkjet printing method.
3 Holt foil printer
3.1 advantages and application
Hot foil printing method is using hot press method to fix the characters on cable’s surface. It’s advantages are the characters are clear and anti-abrasion. Can print dynamic meters. It’s disadvantages are: it needs lots of printer blocks, color tape is comsumption, the electricity is part of comsumption.
3.2 Note
1) While purchasing printing blocks, we should consider it’s universality, and pay attention to the block’s material and rough surface. Usually copper material printing block abrasion is bad, it’s better to choose chrome plating steel material.
2) While choose printing tape, pay attention to it’s quality. Avoid color tape itself has separate layer, and the storage condition of the color tape.
4 Hot press printing
4.1 Advantages and applications
Hot press printing is used for large size cable, the content is sculpted on the surface of printing wheel, different size cable need different size wheel. Most advanced country want hot press printing method.
Hot press method is putting printing device on the cable’s surface, by adjusting the hot pressing wheel and surface tension to fulfill the concave-convex printing.
It’s advantages: Printing effect is clear, character lifetime is long, can’t be erased , no comsumption and free maintenance.
Disadvantages: 1 when producint variety cables, using hot press printing method will add production cost of wheels. 2 The integrity is influenced 3 can not print dynamic meters 4 During production, the cable would swing left and right, while operation incorrect, it will make sratch on the cable surface.
4.2 Note
Because of lots of export products, in most situations the customer ask hot press printing method on cable’s sheathing surface, usually the character height is 8-13mm. When height is less than 8 mm, the characters is clear and has high integrity. And the sheathing surface won’t become thiner, while characters’ height is greater than 8 mm,to gurantee it’s integrity and utility, we should adopt relevant mehods. Hot press printing mehod has high standard on the wheel. While using this mehod, there’s a lot of details to pay attention to, because different material, printing device and technology is also different.
4.2.1 PVC,XLPE,PE, LSZH/HFFR material
1) Hot press printing device
Hot press printing device is designed based on lever principle, some factory product is complex, some factory product is simple, “Z” shape is the simplest device.
2) Hot press printing method and it’s material
Hot press wheel is divided into two types, Integrity type and combination type, like follwing picture: ( left is integrity type, and the right is combination type)
Integrity type printing wheel uses steel tube, al alloy, all aluminum materials etc. It sculpted the characters on the surface of the hot press printer. There are 2 different types of surface of the wheel, one is flat type like the left, the other one is arc type like the right, cross section pictures are as following:
When the characters’ height is greater than 8mm, using flat type can not guarantee it’s uniformity. The other arc type, the wheel surfact has similar shape as cables, this can guarantee the characters’s integrity. Clearness and uniformity. Combination tye is also divided into 2 type, one type is sculpted content on copper rope, the other type is using character blocks.
Integrity type structure wheel hot press printing effect is better than combination type. Because while using blocks type, there will be block shape also printed on the cable surface.
3) Hot press printing character sculpted
While making the printing wheel, it’s necessary to be clarified about the line depth and width. Hot press printing wheel has 2 types sculpted method, Concave and convex type. Most customers want the characters in Convex type which means the sculpted characters is concave type.
4) Installation
Printing effect is not just about it’s height, it’s also important to confirm the device position, during production, after material extrusion, the materials still has high temperature and it’s in flow status. While Printing wheel is near to crosshead, the cable maybe pressed into irregular shape. So it’s better to be placed near water coolinig side. After analysis, when the printer is placed near cooling side, the extruded material has coolend already, it is half flow status and it won’t change it’s shape again. It’s printing effect is better. Some factory placed the printer after cooling, which needs pre-heatment device then print characters.
4.2.2 Rubber material hot press printing method
Hot press printing device usually is equipped between crosshead and Sulfide tub, this device has one set hot press stand, one meter counting wheel, one hot press ball, integrited in the sulfide line.Stainless stell body has fast response to on/off, changing the press blocks to use concave and convex type blocks. And it can adjust the height of the stand according the different cable diameters. There’s one stick at the side of the printing wheel to adjust the pressure. If not using hot press type printing, whole stand can back off to spare more space. Following is the device picture:
This device has simple and convenient advantages, but it has strict standard on the sculpted characters on the wheel. And the sculpted character depth should be adjusted according to the types of rubber and the materials hardness. During actual production process, the rubber is extruded out from crosshead and covering on the wire. Before it’s sulfiding, the printing process is finished. In this way, the wheel has arc surface, the characters is sculpted on arc surface, the arc surface has limited suitable ranges of cable diameters. This needs large amount of printing wheels.
5 Laser printing method
5.1 Technology
Laser printing method uses laser printer to mark the content on the cable surface, it’s principle like Convex mirror concerntrate the light energy to burn the stick.The laser is system processed, the cross convex mirror to concerntrate the energey into small ranges, if the materias has good features absorbing the laser,then the area’s temperature will rise rapidly,according to different materials’ features (like melting point, boiling point, chemical effect) The mechanic accessories have series physical and chemical changes, for example the melting, vapouring, oxidization, coloring. Then generate concave groove, this realize the printing effect.
5.2 Features and applications
Nowadays, using laser printing method is one new technology. Laser printing uses very thin laser bunched energy to print, this belongs to non-contact type printing, There’s no mechanic force on cables during production. And the content can be modified during production. Laser printing has small area effect, character is clear and solid. It won’t abrasion to flat and erased. Low cost and easy operation. No comsumption and free maintenance. No pollution as well. This can realize ordinary mehod that can’t fulfill technology, this method solve the defect of above methods. Suitable cable materials are PVC, XLPE, PE, LSZH, Silicon rubber, EPR, CPE, steel etc. following sheet is the comparision of laser printing method with traditional oil printing method
Laser printing Inkjet printing
Primary cost high Low
Characters Position Any position Any position
Pollution Saint and no pollution Oil pollution
Clearness Thin line this with clearness Wide line characters
Solid Can not erased Can be erased, and influence by environment
Maintenance Easy and free Routine maintenance
Consumption electricity Electricity+ oil + diluter
One year cost Purchasing + electricity Purchasing +oil + electricity
Long time usage electricity Electricity + oil + maintenance
Besides, you can adjust the power to get different depth of characters ( this like hot press printing ) The laser generator has differnet wave length. This makes it feasible to print on different materials like PVC, XLPE, PE, LSZH,CPE, EPR etc. This method is widely used for plastic cables and rubber cables. This can also be used for flexible fire resistance cables, al alloy cables, mining cables’ copper, aluminum,aluminum alloy, steel mental sheath sculpted characters. This method solves the problems printing on special material cables.
Laser type printer installation position is same as inkjet printer, before take-up. Like following picture:
5.3 Note:
While using laser printing method, pay attention to choice of the laser generator, different material has different features in absorbing different wavelenth of laser. So we need to choose suitable laser generator according to the materials. For example the fiber type laser printer and semi-conductor laser generator use 1064 μm wavelength laser. Mental metarials absorb in good effect, that’s why it is used in mental printing. CO2 type laser printer generates 10.6 μm wavelength laser, nonmental material absorb it well. So it is better to used in cable printing. There are some special materials(There’s no color while using 1064 μm wavelength. But while using 10.6 μm red laser, it will melt. This needs 532 μm ( Green laser) or 355 μm ( purple laser) wavelength to mark. Due to the differences of materials, anyother product need to be tested first before equipped in production line. Especially some special materials.
7Ending
1)About traditional oil wheel printing and inkjet printing method, use plasma effect can get good effect
2)For export products, it’s better to hot press printing
3)Laser type printing method is applicable all kinds of plastic material and mental materials. At the mean time, it can fulfill surface printing and concave-convex printing. The effect meets the demand of cables’ lifetime.