Cutting
Cutting is the first stop in the production of FPC raw materials, the quality of its impact on its larger, but also a control point of the cost, due to the high degree of cutting machinery, mechanical performance and maintenance is particularly important. And the precision of the cutting equipment is required to achieve the basic precision of the cut object, so the operator in the operation of the technical proficiency and sense of responsibility for special requirements.
A. Common defects of products: insufficient number, indentation, crease, board warping, oxidation, width.
Uncounting: caused by cutting tolerance, manual operation.
Indentation: caused by the material itself and the operation (caused by the rotation of the cutting machine).
Folds: The joints between the rolled packaging material and the tube shaft, the joints of the material, caused by the operation (caused by the rotation of the cutting machine).
Warping: The tube shaft of the curled packaging material is too small (77mm can be replaced by 152mm), the frozen material (Coverlay) will be naturally flattened after four hours of warming up after taking out of the refrigerator, and over-drying will also cause the material to warp.
Oxidation: The oxidation of the material is mainly related to the humidity of the storage environment and the storage time.
Breadth: The error in the width of the material is caused by the slitting equipment of the material.
B. Recognize the code of raw materials: such as the category of copper foil; manufacturer's code; layer; single and double-sided board; insulation layer category; insulation layer without insulation layer category insulation layer thickness; insulation layer and copper sheet with or without adhesive; copper thickness; copper treatment; width code.
C. Production process requirements:
1. The operator should wear gloves and finger cots to prevent the surface of the copper foil from oxidizing due to sweat stains on the hands.
2. The correct way to rack the material to prevent folding.
3. Don't cut out of shape, and don't destroy the punching position holes and test holes when cutting by hand. If there is no special instructions when the cutting tolerance for a single panel of ± 1mm double panel of ± 0.3mm
4. Cutting size can not have a large error, and pay attention to its verticality, that is, cut for the sheet when the four sides should be perpendicular (<2 °)
5. Material quality, the surface of the material can not have wrinkles, stains, heavy oxidation phenomenon, the cut material can not have burrs, overflow of glue, and so on.
6. Mechanical maintenance: strictly in accordance with the & lt; automatic cutting machine maintenance inspection record table & gt; the implementation of.
Drilling (CNC)
CNC is the first station of the entire FPC process, the quality of the subsequent program has a great impact on the CNC basic process: group boards → playing PIN → drilling → back PIN.
A. Common product defects: tearing glue, size shrinkage.
Pulling glue: A. Adhesive properties (the softening point of the adhesive is 60-90 ℃), B. The number of stacked (normal 9), the resistance, speed, hole diameter (⊙ for 3), drilling conditions (equipment, pads, into the number of cutters, number of retractors) (into the number of cutters 0.6M / min, speed of 75,000 / min, retract the number of cutters 25M / min, bake 150 ℃ for an hour after the slicing).
Dimensional expansion and contraction: The normal standard is 0.1% dimensional expansion and contraction after the material is sliced and drilled at 150℃ for 1 hour, generally the MD direction will be contracted and the TD direction will be expanded.
B. Production Process Requirements
Selection of Coverlay→Coverlay→Tape Bonding→Arrowhead (mark)
1. Basic Coverlay Requirements:
Single Coverlay 15 sheets, Single Copper 10 sheets or 15 sheets, Double Coverlay 10 sheets, Single Copper 10 sheets or 15 sheets
Yellow Coverlay 10 sheets or 15 sheets, White Coverlay 25 sheets, Auxiliary Strength Board, and Double Coverlay 10 sheets, Single Copper 10 sheets or 15 sheets
White Coverlay 10 sheets or 15 sheets. Coverlay 25 sheets Auxiliary plate 3-6 sheets according to the situation
2. The main function of coverlay:
Reduce the hole burr.
Preventing the drill and pressure foot from pressing on the material surface.
Makes it easy to locate the center of the drill tip to avoid skewing of the drilling position.
Takes away the heat generated by the friction between the drill bit and the hole wall and reduces the twisting of the drill bit.
3. Control of drilling needles
Control of the number of times of use.
Methods for recognizing new drills.
Inspection of new drill bits.
4. Quality Control Points
Confirm the correct hole position and number of holes according to the drill sheet and drilling data, and check the broken pins to see if the drilled holes are
completely open.
The appearance of the quality of the product should not have the bad phenomenon of copper warping and burrs.
5. Production Process Control Points
Product Confirmation
Process Confirmation
Combination Confirmation
Size Confirmation
Position Confirmation
Program Confirmation
Tool Confirmation
Coordinate Confirmation
Direction Confirmation.
6. common bad performance and causes of operation in the production
a. needle breakage :① improper operation of the drilling machine, ② problems with the drill bit, ③ too fast into the knife, etc.
b. burrs :① cover, pad is not correct, ② drilling conditions are not correct, ③ static adsorption, etc.
7. the main reasons affecting the quality of drilled holes:
a. the operator; technical skills, responsibility, and the ability to work in the machine. Technical ability, responsibility, proficiency
b. Drill needles; material, shape, number of drills, drill tip
c. Platens; pads; material, thickness, thermal conductivity
d. Drill presses; vibration, positional accuracy, clamping force, auxiliary performance
e. Drilling parameters; split/single processing methods, number of revolutions, speed of entry and exit tools.
f. Processing environment; external vibration, noise, temperature, humidity
Grinding
Grinding is an auxiliary process that may be utilized many times in the FPC process, as a pre-treatment or post-treatment of other processes. Generally, the boards are first acid washed, micro-etched or oxidation-resistant, and then brushed with nylon brushes to remove impurities, blackened layers, and residue on the board surface. The surface of the board is then brushed with a nylon wheel brush to remove impurities, blackened layers, residual glue, and so on.
A. Grinding Procedures: Input - blackened layer - washing - grinding brush - pressurized washing - cutting water and squeezing dry - blow-drying - drying - discharging
B. Types of Grinding:
1. To be attached to the film: double-sided panels to de-oxidize, stretching (aperture offset) Single-panel: de-oxidized
2. To be false sticker Coverlay: sanding, de-red spot (after stripping the film Na (NaOH residue after stripping the film), de-oxidized
3. To be false paste paving strong: grinding, cleaning
4. To be plated: grinding, cleaning, increase the adhesion
5. After plating: drying, improve the gloss
C. Surface Quality Requirements:
1. Need to grind the place all have a uniform grinding traces of brushes.
2. The surface should be dried completely, no oxidization or water droplet residue.
3. There should not be any wrinkles and crumpling caused by the water cutting roller.
4. There should be no copper skin warping due to abrasion and brushing, or copper powder accumulating on the edge of the coverlay and warping.
D. Operation and production of common defects and prevention:
1. The surface of the water droplet traces, this time you should check the sponge roller is too wet, should be cleaned regularly, squeeze the water.
2. Oxidized water is completely removed, check whether the pressure of the brush wheel is sufficient, whether the transfer speed is too fast.
3. The blackened layer is not cleanly removed
4. The brushing and grinding is not uniform, you can use a single sheet of copper foil to check whether the brushing and grinding is uniform.
5. Wrinkles or broken wires due to cardboard.
E. Common product defects: board warping, oxidation, size shrinkage.
Panel warping: left and right at the same time brushing (polishing) more flat, the distance between the shaft surface and the board should not be less than 1CM.
Oxidized: after pickling or brushing.
Size shrinkage: can be changed to sulfuric acid cleaning, 1200 mesh sanding.
Copper plating (copper or black hole, PTH)
PTH that is, in the absence of external current, through the plating solution of the autocatalytic (palladium and copper atoms as a catalyst) redox reaction, so that the copper ions precipitation plating in the activated treatment of the hole wall and the surface of the copper foil, also known as the chemical plating of copper or autocatalytic plating of copper
A.PTH chemical reaction equation.
B.PTH process and the role of each step
The whole hole → water washing → micro-etching → water washing → acid washing → water washing → water washing → water washing → pre-impregnation → activation → water washing → speed → water washing → water washing → water washing → chemical copper → water washing.
1. Hole cleaning; clean the surface of the plate, polarize the negative charge of the hole wall into a political charge, which is conducive to the adhesion of negatively charged palladium colloid.
2. Micro-etching; cleaning the surface of the plate; roughening the surface of the copper foil to increase the adhesion of the coating.
3. Acid washing; cleaning the plate; removing oxidized layer and impurities.
4. Pre-impregnation; to prevent contamination of the activation tank.
5. Activation; to make the palladium colloid attached to the pore wall.
6. Rapidization; reduce Pd ions to Pd atoms, so that the chemical copper can be tin-plated.
7. Chemical copper: copper is deposited on the hole wall and the surface of copper foil by chemical reaction.
C. PTH production of bad conditions in the treatment
1. hole without copper
a: activation of palladium adsorption deposition is not good.
b: Speed chemical tank: speed chemical solubility is not right.
c: chemical copper: the temperature is too low, so that the reaction can not be carried out reaction speed is too slow; tank liquid composition is not right.
2. The hole wall has particles, rough
a: chemical tank has particles, uneven deposition of copper powder, must be installed filter device.
b: The plate itself has burrs on the hole wall.
3. Blackening of the plate surface
a: the chemical bath composition is not right (NaOH concentration is too high)
b: not enough bath builder when building the bath.
D. Product quality inspection of common defects: broken holes, surface roughness, the surface of the glue residue, size shrinkage. (Black holes are carbon black deposits)
Broken holes: caused by glue pulling during drilling.
Surface roughness: caused by excessive current density during copper plating.
Surface residual glue: caused by raw material coating, cutting and cutting (residual nitrate glue left on the material)
Size shrinkage: normal copper plating produces size shrinkage of 0.04-0.07%, affecting the size of the shrinkage of the product production and use of the ambient temperature, brushing board, etching, design-related. The more copper foil remains, the smaller the dimensional shrinkage.
Copper plating:
Copper plating is to improve the uniformity of plating in the holes, to ensure that the entire layout (holes and holes near the entire plating) coating thickness to meet certain requirements.
A. Process control:
1. product confirmation
2. process confirmation
3. liquid confirmation
4. confirmation of machine parameters.
B. Quality control:
Chemical copper should be poured every week, the role of copper deposited in the bottom of the tank, the bottom of the tank more and more copper, the more the consumption of potion, thus making the cost higher.
1. Through: the first slot draw 2, 20 times magnification to check the hole wall whether the copper-plated completely attached through.
2. Surface quality: the surface of the copper foil must not have burnt, peeling, granular, pinhole and spotting bad phenomena.
3. Adhesion: in any one place on the board edge of about 2.54 * 2.54cm2 area from the axis of the horizontal axis of the slice each cut 10, and then 3M tape paste 3 minutes after the vertical upward pick up there is no shedding phenomenon.
Section experiment:
A. Operation procedure:
1. Prepared slices of the required acrylic powder and solution, petroleum jelly, fixtures, utensils.
2. According to the requirements of the sample production test piece.
3. Now the inner surface of the vessel evenly coated with a layer of lubricating effect of petroleum jelly.
4. The specimen is clamped in a jig and placed in the vessel.
5. Mix the acrylic powder and acrylic solution in the ratio of 10:8 and slowly pour into the vessel.
6. Take it out directly after it solidifies and molds.
7. The slices were placed on a metallographic specimen pre-grinder and ground and polished until they met the requirements, and then observed with a metallographic microscope and recorded their values.
B. Notes:
Paste film:
It is the dry film pasted on the plate, after the dew light after the development of the line is basically molded, in the process of the dry film mainly plays the function of the image transfer, but also in the process of etching play a role in the protection of the line.
A. Dry film is mainly composed of: PE, photoresist, PET. Among them, PE and PET only play the role of protection and isolation. Photoresist includes: linker, initiator, monomer, adhesion promoter, color.
B. Work Requirements:
1. Keep the dry film and board surface clean.
2. Flatness, no bubbles and wrinkles.
3. Adhesion to meet the requirements, high density.
C. Work quality control points:
1. In order to prevent the phenomenon of wire breakage during the film, the surface of the copper foil must be removed with a dust-free paper to remove impurities.
2. The temperature, pressure and speed of the heating roller should be set according to the different plates.
3. Ensure that the direction of the copper foil hole in the same orientation.
4. Prevent oxidation, do not directly touch the surface of the copper foil, if the phenomenon of oxidation to use fiber brush to brush off the oxide layer.
5. There should be no scars on the heating roller to prevent wrinkles and poor adhesion.
6. After the film to stay 15min-3 days, and then go to the dew light, too short a time will make the dry film by UV light irradiation, the occurrence of organic polymerization reaction is not complete, too long is not easy to be hydrolyzed, the occurrence of residual lead to poor plating.
7. Often use dust-free paper to wipe away impurities on the heating roller and overflow glue.
8. To ensure good adhesion of the film.
D. Quality Confirmation:
1. Adhesion: After the film to Hitachi test negative test, after exposure and development of the line can not be bent deformation or broken, etc. (with a magnifying glass to detect)
2. Flatness: must be flat, there can be no wrinkles, bubbles.
3. Cleanliness: No more than 5 points of impurities per sheet.
Lucent
It is through the action of dry film to make the line graphic transfer to the top of the board.
A. Key points:
1. keep the negative and the board clean during the operation;
2. the negative and the board should be aligned correctly;
3. there should be no air bubbles and impurities; be careful to expose the holes when you put the film.
4. Double-sided board work should be padded with black paper to prevent exposure.
B. Quality Confirmation:
The specification of the negative, the exposure energy of the exposure machine, and the tightness of the negative and the dry film will all affect the precision of the line.
1. Accuracy
a. Positioning hole offset +0.1/-0.1 or less
b. Soldering point of the tin ring can not be less than 0.1mm (can not be holes in the principle of broken)
c. Through the hole of the tin ring can not be less than 0.1mm (can not be holes in the principle of broken)
2. Line quality: there can not be negative factors of the fixed broken line, pinhole or short circuit phenomenon. pinhole or short circuit phenomenon.
3. Vacuum purpose: to improve the film and dry film contact tightness to reduce astigmatism.
4. Exposure energy level on the quality of the impact:
a. Low energy, exposure is not enough, after the development of the resist is too soft, gray color, etching resist destruction or floating, resulting in line breaks.
b. High energy, it will cause overexposure, then the line will be shrunken or the exposure area is easy to wash out.
Development:
Development means that the board with dry film that has been exposed to light is treated with developing solution (7.9g/L sodium carbonate solution), which washes away the dry film that has not been irradiated by UV light and retains the dry film that has been irradiated by UV light and undergoes a polymerization reaction to make the line basically formed.
A. Factors affecting the quality of the developing process:
1. Composition of the developing solution.
2. Developing temperature.
3. Developing pressure.
4. Uniformity of developer distribution.
5. Speed of machine rotation.
B. Process parameter management main control points:
1. Liquid solubility
2. Developing temperature
3. Developing speed
4. Spray pressure.
C. Developing operation quality control points:
1. There should be no water droplets on the trigger of the discharge port, should be blown clean.
2. There should not be any untorn dry film.
3. The image should be complete, the line should not be jagged, bent, thin and other conditions.
4. After the image of the bare copper surface with a knife to gently scrape the dry film must not fall off, otherwise it will affect the quality of the moment job.
5. Dry film line width and negative line width control within +/-0.05mm error.
6. The complex side of the line is placed downwards to avoid residual film residue and reduce uneven development caused by the pool effect.
7. According to the solubility of sodium carbonate, dry film load and use time to update the film solution to ensure the best development effect.
8. Control the level of developer and water.
9. Blow drying wind should be kept inward 5-6 degrees.
10. Should be regularly cleaned in the tank and nozzle, nozzle in the scale, to prevent impurities contamination of the plate and cause uneven distribution of the developer.
11. Prevent the operation of the cardboard, cardboard should be stopped when the rotation device, should immediately stop the release of the board, and take out the plate to the middle of the development table, such as not fully developed, due to the second development.
12. After the development of blow-drying boards should be separated by absorbent paper to prevent dry film adhesion and affect the quality of the moment.
D. Quality Confirmation:
1. Integrity: After developing the bare copper surface with a razor blade to gently scrape the dry film should not be left.
2. Appropriateness: line edges, can not be jagged or line obviously thin, the phenomenon of warping, after the development of the dry film line width and the negative line width needs to be within +0.05/-0.05m.
3. Surface quality: need to be blown dry, no water droplet residue.
Etching (etching stripping):
Etching is at a certain temperature conditions (45 +5 ℃) etching solution through the nozzle uniformly sprayed to the surface of the copper foil, and no etch resist protection of copper redox reaction, and the unwanted copper reaction off, exposing the substrate and then stripping the film treatment to make the line shape.
A. The main components of etching solution: copper chloride, hydrogen peroxide, hydrochloric acid, soft water (solubility has strict requirements)
B. Quality requirements and control points:
1. There can be no residual copper, especially the double-sided board should be noted.
2. There can be no residual glue, otherwise it will cause copper or plating adhesion bad
3. Moment speed should be appropriate, do not allow excessive etching caused by line thinning, the moment the line width and the total pitch should be the focus of this site control.
4. Line soldering points on the dry film shall not be flushed separation or fracture
5. Etching stripping film after the plate does not allow oil, impurities, copper skin warping and other bad quality.
6. Put the plate should pay attention to avoid cardboard, to prevent oxidation.
7. Should ensure that the moment of the uniform distribution of liquid, in order to avoid the front and back or the same side of the different parts of the etching is not uniform.
C. Process control parameters:
1. Etching solution temperature: 45 +/-5 ℃
2. Hydrogen peroxide solubility: 1.95 ~ 2.05 mol / L
3. Stripping solution temperature: 55 +/-5 ℃
4. Etching machine safe to use the temperature of ≤ 55 ℃
5. Drying temperature: 75 +/-5 ℃
5. +/-5℃
6. Spacing between front and rear plates: 5~10cm
7. Specific gravity of copper chloride solution: 1.2~1.3g/cm3
8. Solubility of hydrochloric acid: 1.9~2.05mol/L
9. Angle of release plate, guide plate, and switching state of upper and lower spray nozzles
D. Quality confirmation:
1. Line width: etching standard line is .2mm & 0.25mm, its etching shall be within +/-0.02mm.
2. Surface quality:
a. No wrinkles, scratches, etc.
b. No copper residue by translucent inspection.
c. The line must not be deformed
d. No oxidized water droplets
E. Common product defects: copper residue, broken lines, discoloration, size shrinkage, board warping.
Copper residue: mainly the use of etching solution is not appropriate to produce, you can change the solution.
Broken line: copper foil without dry film protection (after pickling dry film adhesion bottom), dry film blistering, excessive etching.
Discoloration: oxidation or expiration of raw materials, acidic and alkaline properties of materials.
Dimensional expansion and contraction: the influence of residual copper.
Warping:etching tank is left too long, speed of etching tank.
Glossy tin-lead
A. Common defects in the process and their causes:
1. Poor bonding (poor adhesion). Poor pretreatment; excessive current; copper ions and other contamination.
2. The plating layer is not bright enough. Insufficient additives; tin-lead ratio is not appropriate.
3. Gas precipitation is serious. Too much free acid; divalent tin-lead concentration is too low.
4. Turbid plating. Too much tin-lead colloid, the formation of precipitation.
5. Plated layer is dark. Too much anode mud; copper foil contamination.
6. Tin plating thickness is large. Plating time is large;
7. Tin plating thickness is small. Plating time is not enough
8. Exposed copper. There is overflowing glue
B. Quality control: 1 minute can be plated 1um thickness when the current density is 2ASD.
1. The first piece of inspection must be 3M600 or 3M810 tape test pull, to verify its adhesion
2. should check whether the plated point is completely plated, there can not be unplated and exposed copper
3. there must be a glossy, there can not be blackened, rough or burnt
4. x-ray thickness gauge to measure the thickness of the plating layer
C. Plating Decision factors for plating conditions:
1. Selection of current density
2. Size of plated area
3. Requirement of plating thickness
4. Control of plating time
D. Appearance inspection:
1. Measurement of plating thickness by x-ray meter
2. Plated spots are completely plated, no irregularities in the thickness of unplated spots are allowed. There should be no abnormal phenomenon that the plated point is not plated
3. The plated layer should not be blackened or rough, burnt
4. The plated layer should not have pockmarks, exposed copper, color difference, holes broken, uneven phenomenon
5. 3M600 or 3M810 adhesive tape should not be peeled off phenomena when trying to pull it
False Stickers (Laminating):
False Stickers, i.e., Protective Film, Reinforcement Plate and Backing. Reinforcement plate and adhesive backing; protective film is mainly insulating, protect the line against drought tin, increase the flexibility of the soft board and other roles; reinforcement plate is mainly to improve the mechanical strength, guide the FPC terminals inserted into the connector role; adhesive backing is mainly to play the role of fixed.
A. Operating procedures:
1. Preparation of tools, to determine the number of semi-finished products to be false stickers, ready to really coverlay semi-finished products.
2. Tear off the release paper of Coverlay.
3. Copper foil should not be oxidized, check and clean the copper foil: brush the surface lightly to remove debris or impurities.
4. The correct coverlay will be fixed with an electric iron according to the working instructions and the position and regulation of the inspection standard card.
5. The semi-finished product after the false sticker should be sent to the hot pressing station as soon as possible for pressing operation to avoid oxidation.
B. Quality control focus:
1. Requirements for work instructions and inspection standard card of the physical control coverlay exposed and drilling position is completely correct.
2. The exact offset of the coverlay alignment of the welded and outlet ends shall not exceed the provisions of the work instructions and inspection standard cards.
3. If tin or nickel gold plating is required, a plating nibble must be left, generally 5cm.
4. There must be no oxidation on the copper foil, no burrs on the exposed edges of the coverlay, and no impurities left inside the coverlay.
5. Perform quality sampling.
6. Work tools must not be placed on the wrench, otherwise there is a risk of scratching or crushing.
C. Appearance inspection:
1. No oxidization on copper foil.
2. The bare edge of the covering film (coverlay) and the edge of the laying of the strong must not have burrs.
3. The coverlay and reinforcement board must not have impurities.
3. The reinforcing plate must not be missed.
4. The products using machine operation should be inspected to ensure that there are no air bubbles, poor lamination, and shifting of the combination.
Pressing (hot pressing):
Hot pressing operation includes traditional pressing, cold pressing, rapid pressing, hot baking and other steps; the purpose of hot pressing is to make the protective film or reinforcing plate completely bonded to the board, according to the curing method can be divided into pressure-sensitive adhesive and heat-setting adhesive, through the temperature, pressure, pressing time, sub-processing materials, such as the combination of the way of combining the layers of the control in order to achieve the purpose of good adhesion, and minimize the occurrence of pressure during the operation. To minimize the occurrence of pressure damage, air bubbles, wrinkles, overflow of adhesive, broken lines and other defects during the operation, we classify them into single-side pressing and double-side pressing according to the combination of the sub-materials.
A. Fast pressure:
1. Combination: single-sided pressure and double-sided pressure, generally used single-sided pressure.
2. Auxiliary materials used and their role
a. Glass fiber cloth: isolation, release
b. Nefflon: dust, anti-pressure injuries
c. Burning iron plate: heating, gas
B. Traditional pressure:
1. Combination of ways: single-sided and double-sided pressure
2. p>a. Talcum powder: reduce stickiness, prevent wrinkles
b. TPX: isolation, dust and impurity prevention
c. Cardboard: cushioning pressure
d. Aluminum alloy plate: flatness
C. Important operating parameters:
Temperature, pressure, nesting method, pressing time
D. Common defects in production and their causes
1. Air bubbles:
a. Silicone film, cardboard and other auxiliary materials are not used
b. Steel plate is not flat
c. Protective film expired
d. Parameter setting errors, such as high pressure, pre-pressure time is too short.
e.Wrong way of layout
2. Pressure injuries:
a.Auxiliary materials are not clean
b.T.P.X placing problem
c.Fiberglass cloth placing problem
3. Reinforcement plate shift
a.Instantaneous pressure is too high
b.Reinforcement plate is too thick
c.Reinforcement plate false paste not securely (the plate false paste). Board false paste is not firm (grinding quality is not good)
4. overflow of glue:
a. auxiliary material adhesive resistance is not enough
b. protective film burr is more serious
c. parameter and its layout is wrong, such as fast pressure is too large.
5. Total Pitch is not good:
a. Wrong pressing method
b. Wrong calculation of shrinkage rate
E. Quality Confirmation:
1. After pressing, the film must be flat, no wrinkles, crumpling, bubbles, curling and so on.
2. The line must not be pulled and broken due to the influence of pressing.
3. The coverlay or reinforcement board must be fully integrated and must not be peeled up by hand.
F. Common product defects: air bubbles, board buckling, dimensional expansion and contraction, glue overflow, creases.
Bubbles: A. Material with the way (such as double-sided board 1OZ substrate with 1.4MIL glue film), B. Material expiration date, C. Material storage conditions, D. Pressure laminating machine flatness, pressure imbalance, equipment problems, the more positive or change the pallet, E. Auxiliary material options, the softening point of TPX is 175 ° C, soluble in 240 ° C. The softening point of TPX is 175 ° C, solvency point.
Panel warping: material matching is not the same class, the pressure of the equipment is not the same (with the sense of color line measurement equipment), half a year to correct.
Dimensional shrinkage: the pressure of the press, uneven force, and temperature rise and fall related (slow rise and fall), generally speaking, the traditional press size shrinkage is larger, fast press size shrinkage is smaller.
The amount of glue overflow: more than 75% of the exposed copper area, related to the raw material (IPC standard is 0.3mm, factory standard is 0.2mm-0.15mm), and process-related (pressure imbalance), material versatility, compression and retention period is to determine the amount of overflow of the main points.
Folding: TPX folding (equipment).
Electroplating
A. Production process:
B. Common product defects: copper exposure, oozing plating.
Copper exposure: Coverlay adhesive penetration, CCL peeling; copper surface adhesive residue (occurs with rapid pressing).
Plating: the working temperature of gold plating is 90-95℃, the working temperature of gold plating is 45℃, the working temperature of tin gold is 16℃, the working temperature of tin spraying (the ratio of tin to lead is 3:7) is 245-260℃/3 seconds, the working temperature of pure gold is 288℃/10 seconds.
Screen Printing:
A. The basic principle of screen printing:
Using polyester or stainless steel mesh as a carrier, the pattern of positive and negative pieces of the direct latex or indirect plate mode transfer to the mesh to form a stencil, as the opposite printing tool.
B. Classification of inks used for printing and their functions.
1. anti-soldering ink: insulation, line protection
2. text: marking line marking, etc.
3. silver paste: anti-electromagnetic interference
4. peelable adhesive: anti-plating
5. acid-resistant agent: filler, anticorrosive agent
C. Quality Confirmation
1. the printing of the direction of location of the front and back must be consistent with the work instructions and inspection standards card on the physical Work instructions and inspection standards on the card in kind consistent.
2. There should be no haloing, fixed line breaks, pinholes
3. Generally, the overprinting logo is aligned with +0.5mm/-0.5mm, such as the work instructions and inspection standards on the card have special screen printing requirements, to its best.
4. After conveying the degree of hot baking, should be 3M tape test pull, can not have the phenomenon of ink fall off.
Note: The temperature of hot baking should be suitable to avoid the melting of tin-lead in some semi-finished products with glossy tin-lead.
SMT:
SMT, or surface mount technology, is a process whereby parts are soldered to the surface of a circuit board, so that the solder pads on the surface of the board and the ends of the parts are combined with solder.
A. The main conditions for good soldering:
1. to ensure that the metal surface of the good soldering and good soldering conditions required to match
2. to select the appropriate flux
3. the correct composition of the solder alloy
4. enough heat when the right temperature profile.
B. Common defects:
1. conn: parts deformation, foot skewed, solder resist climbing open.
2. FPC: bubbles, pressure, wrinkles, printing layer peeling, miswelded parts.
3. Solder pad: short circuit, empty soldering, cold soldering, seepage of tin, tin tip, tin more, packet soldering, textbook
4. other: tin beads, tin slag, sticky solder resist, chip residue.
C. SMD heavy program: the same product heavy action can not be more than 2 times.
1. Short-circuit: directly use the soldering iron to pull out the short-circuit tin.
2. Empty soldering: directly use the iron to fill the tin.
3. Cold Soldering: Re-pass the cold soldered product back to the soldering furnace.
4. Insufficient amount of solder paste: directly use the soldering iron to make up the tin.
5. Pack soldering: Use the soldering iron directly to suck out the excess tin.
D. Common product defects: burst board, penetration (tin).
Burst plate: manual soldering will occur, automatic SMT will not occur, the general temperature resistance of the material is 320 ℃, in the reflow soldering before 150 ℃ / 1 hour baking.
Infiltration (tin): and material-related; and temperature-related, high-temperature time is too long, the normal 3 seconds, can be tested with a tin furnace.
XVII. Post-processing:
A. Processing methods are divided into the use of machinery and not use two kinds of machinery, the main processing is to paste the shrapnel, adhesive backing or reinforcing plate, processing operations should pay attention to prevent poor fit, bubbles and wrinkles and other bad quality problems.
B. Classification of adhesive tapes: commonly used without the substrate of the pressure-sensitive double-sided adhesive
1. pressure-sensitive adhesive
2. heat-curing adhesive
3. water-based adhesive
C. Definition of pressure-sensitive adhesive
1. natural visco-elastic qualities
2. fast and long-lasting adhesion
3. light pressure with a good characteristic
3. Good characteristics
4. Good holding power
5. Sufficient cohesion and elasticity
D. Benefits of pressure-sensitive adhesive:
1. No pre-treatment steps such as coating or mixing.
2. Uniform adhesive volume
3. Convenient and quick to use
4. Can be punched and cut into a variety of shapes
5. Long-lasting viscoelasticity prevents brittleness and shortening of cracks
6. Odorless, tasteless, and solvent free when used.
E. Quality Confirmation:
1. Backing: Do not touch or shrink the glue by hand and cause the backing to be incomplete, and do not miss the sticker.
2. Paste shrapnel: The positioning holes of the shrapnel should not be broken after the shrapnel is pasted.
The shrapnel must not be shifted or have impurities, and the edges of the shrapnel must not have burrs.
3. Reverse folding: Reverse folding should not have serious overflow of glue, should be flat, and should not have the situation of popping out after folding.
Refolding position must be consistent with the work instructions on the inspection standard card in kind.
The size of the refolding must be consistent with the tolerance of the size on the work instruction and inspection standard card.
4. Combination: with the work instructions and inspection standards card on the physical location of the sticker, the direction is consistent.
5. Stick opp adhesive: the position of the paste should be correct, should be flat, no wrinkles, bubbles.
6. Paste conductive cloth: flat, no burrs, paste bias.
7. Processing reinforcement: the position is correct, flat, no burrs, leakage paste.
18. Punching (punching):
A. Common defects: punching bias, pressure injury, punching the reverse, rough edges, copper warping, FPC damage and other phenomena.
B. Process control focus: the correctness of the touch, direction, size accuracy.
C. Key points of the operation:
1. The range of hand cutting should not exceed the width of the cutting line.
2. The product to be measured after cutting must have its conductive line cut off.
3. The upper hole must not be broken when punching and testing
4. The surface of the product must not be scratched or wrinkled.
5. Punching deviation should not exceed the specified range.
6. The correct use of the same material number of the mold.
7. There must not be serious burrs or pulling material, tearing or abnormal bumps or residual glue and laying strong shift, the phenomenon of release paper off.
8. Work safely and in accordance with the safety manual.
D. Common causes of defects:
1. Punching deviation
a. Man-made reasons (because the FPC softer, the personnel of the position of the punch if the tension, the force will be pulled to the excessive deformation of the holes)
b. Other stops
①. Automatic cutting (cut off the positioning hole)
②. Exposure (hole deviation)
3. CNC
4. Screen printing, etching (poor printing, etching will be etched too large aperture)
5. False sticker, processing (cover the punched holes)
2. Pressure injury
a. Pressure injury of the lower die
b. Composite die
3. Copper warping
a: slow speed, low pressure
b: blunt cutter mouth (off the plate and the cutter die must not have a gap, which is easy to produce pulling)
Punching the reverse
Feeding the wrong direction (in general, the copper die is not suitable to be used as a die). Wrong (in general, the surface of the copper mold is facing up, the surface of the knife mold is facing down)