深圳市红绿蓝自动化技术有限公司

UV Laser Processing Applications In The PCB Industry
Date: 2018-07-26Read: 3958

For Laser Cutting Or Drilling In The Circuit Board Industry, Only A Few Watts Or More Than A Watt Of UV Laser Can Be Used, Without The Need For Kilowatt-Level Laser Power, In Consumer Electronics, Automotive Or Robotics, Flexible Circuit Boards Use Becomes Increasingly Important. Due To Its Flexible Processing, High-Precision Machining And Flexible And Controllable Machining Processes, UV Laser Processing Systems Have Become The First Choice For Flexible Circuit Boards And Thin PCB Laser Drilling And Cutting.

Today, The Long-Life Laser Source Of The Laser System Is Almost Maintenance-Free. In The Production Process, The Laser Level Is 1 And It Is Safe Without Additional Protection. The LPKF Laser System Is Equipped With A Vacuum Cleaner That Does Not Cause Harmful Emissions. Together With Its Intuitive And Easy-To-Use Software Control, Laser Technology Is Replacing Traditional Mechanical Processes, Saving The Cost Of Special Tools.

Is The CO2 Laser Or UV Laser?

For Example, When The PCB Is Divided Or Cut, A CO2 Laser System With A Wavelength Of About 10.6 Μm Can Be Selected. The Processing Cost Is Relatively Low, And The Laser Power Provided Can Reach Several Kilowatts. However, It Generates A Lot Of Heat During The Cutting Process, Causing Severe Carbonization Of The Edges.

The UV Laser Has A Wavelength Of 355 Nm. Laser Beams Of This Wavelength Are Very Easy To Optically Focus. UV Lasers With Less Than 20 Watts Of Laser Power Have A Spot Diameter Of Only 20 Μm – And The Energy Density Is Comparable To The Sun's Surface.

Advantages Of UV Laser Processing

UV Lasers Are Especially Suitable For Cutting And Marking Hard Boards, Soft And Hard Bonded Boards, Soft Boards And Their Accessories. So What Are The Advantages Of This Laser Process?

In The Field Of Circuit Board Sub-Boards In The SMT Industry And Micro-Drilling In The PCB Industry, UV Laser Cutting Systems Show Great Technical Advantages. The Laser Cuts One Or More Times Along The Desired Profile, Depending On The Thickness Of The Board Material. The Thinner The Material, The Faster The Cutting Speed. If The Accumulated Laser Pulse Is Lower Than The Laser Pulse Required To Penetrate The Material, Only Scratches Will Appear On The Surface Of The Material; Therefore, The QR Code Or Bar Code Can Be Marked On The Material For Subsequent Tracking Of The Process Information.

The Pulse Energy Of The UV Laser Acts Only On The Material For A Period Of Microseconds. At A Few Micrometers Beside The Slit, There Is No Significant Thermal Influence, So There Is No Need To Consider The Damage Caused By The Heat Generated By The Component. The Lines And Solder Joints Near The Edges Are Intact And Burr-Free.

In Addition, LPKF UV Laser System Integrated CAM Software Can Directly Import Data Derived From CAD, Edit The Laser Cutting Path, Form Laser Cutting Contour, Select The Processing Parameter Library Suitable For Different Materials, And Directly Laser Processing. The Laser System Is Suitable For Both Mass Production And Sample Production.

Drilling Application

The Through Holes In The Board Are Used To Connect The Front And Back Lines Of The Double Panel Or To Connect Any Interlayer Lines In The Multilayer Board. In Order To Conduct Electricity, It Is Necessary To Plate The Hole Walls With A Metal Layer After Drilling. Nowadays, The Traditional Mechanical Method Has Been Unable To Meet The Requirements Of The Smaller And Smaller Diameter Of The Drill Hole: Although The Spindle Speed Is Increased, The Radial Speed Of The Precision Drilling Tool Is Reduced Due To The Small Diameter, And The Required Machining Effect Cannot Be Achieved. In Addition, From An Economic Perspective, Tool Wear That Is Prone To Wear Is Also A Limiting Factor.

For The Drilling Of Flexible Circuit Boards, LPKF Has Developed A New Laser Drilling System. The LPKFMicroLine 5000 Laser Unit Is Equipped With A 533mm X 610 Mm Work Surface For Automated Roll-To-Roll Operation. When Drilling, The Laser Can Cut Out The Micropore Profile From The Center Of The Hole, Which Is More Accurate Than The Normal Method. The System Can Drill Micropores With A Minimum Diameter Of 20 Μm On Organic Or Non-Organic Substrates At High Aspect Ratios. Such Precision Is Highly Desirable For Flexible Circuit Boards, IC Substrates, Or HDI Boards.

Prepreg Cutting

In The Manufacturing Process Of Electronic Components, What Conditions Are Required To Cut The Prepreg Material? Early In The Industry, Prepreg Materials Have Been Used In Multilayer Boards. The Various Circuit Layers In The Multilayer Circuit Board Are Pressed Together By The Action Of The Prepreg; According To The Circuit Design, Some Areas Of The Prepreg Need To Be Cut And Opened Before Being Pressed.

A Similar Procedure Applies To The FPC Cover Film. The Cover Film Is Usually Composed Of Polyimide And A Rubber Layer Having A Thickness Of 25 Μm Or 12.5 Μm And Is Easily Deformed. A Single Area (Such As A Pad) Does Not Need To Be Covered By A Film Cover For Later Assembly, Connection, And The Like.

This Thin Material Is Very Sensitive To Mechanical Stress – It Can Be Easily Done By Non-Contact Laser Machining. At The Same Time, The Vacuum Adsorption Table Can Fix Its Position Well And Maintain Its Flatness.

Soft And Hard Board Processing

In The Soft And Hard Bonding Board, The Rigid PCB Is Pressed Together With The Flexible PCB To Form A Multilayer Board. During The Pressing Process, The Flexible PCB Is Not Pressed And Bonded With The Rigid PCB. The Rigid Cover Covering The Flexible PCB Is Cut And Separated By Laser Deep Cutting, Leaving A Flexible Part To Form A Soft And Hard Bonding Board.

Such Deepening Processing Is Also Suitable For Blind Groove Machining Of Surface-Embedded Integrated Components In Multilayer Boards. The UV Laser Precisely Cuts The Blind Grooves Of The Target Layer Separated From The Multilayer Board. In This Region, The Target Layer Is Not Connected To The Material Covered Thereon.

Efficient Board For PCB And FPC

The SMT Rear Panel Is A Circuit Board On Which A Variety Of Electronic Components Have Been Assembled, And The Process Is Already At The End Of The Production Chain. For The Splitter Board, Different Technologies Can Be Chosen: For The Usual PCBs, The Traditional Knife Cutting, Stamping And Contour Milling Processes Are Preferred. For More Complex Electronic Circuits And Thin Substrates, Especially For Mechanical Stress, Dust And Dimensional Deviations, UV Laser Cutting Is More Advantageous. The Following Three Charts Evaluate These Three Methods From Different Factors.

For The Complete Contour Cutting, LPKF Germany Recommends That The Thickness Of The Cutting Material Not Exceed 1.6mm Depending On The Laser Source Used. For Some Thicker Materials, As Well As Expensive Assembly Components, The Safety And Quality Aspects Are Prioritized, While The Cutting Time Is Second.

By Cutting The Breakpoint Plate, The Laser System Cuts Off The Joint By A Previously Described Process. This Cutting Process Can Be Carried Out Close To The Components On The Edge, Which Is Also Very Economical For Thicker Boards.

Other Application Areas

Due To The Short Wavelength Of The UV Laser, It Is Suitable For Most Material Processing. For Example, It Can Be Used In The Electronics Industry:

Processing TCO/ITO Glass Without Damage To The Substrate
Drilling Holes In Flexible Or Thin Materials
Solder Mask Or Cover Film Opening Window
Rigid/Flexible Circuit Board Sub-Board
Slotting
Rework Of Assembled Or Unassembled Boards
Cutting Sintered Ceramics
Precision Cutting LTCC
UV Laser Processing Applications In The PCB Industry

Not Limited To The Processing Of The Board, The UV Laser System Can Simultaneously Cut, Write And Drill The LTCC Components In One Machining Operation.