KYOCERA SGS Precision Tools Group
KYOCERA SGS Precision Tools Group
Drilling high-aspect-ratio holes in Printed Circuit Boards (PCB) presents unique challenges. Unlike standard machining, PCB micro drills lack the rigidity of larger tools and operate in composite materials that generate excessive heat and rapid tool wear. Achieving precision requires a strategic approach that ensures accurate hole placement, superior hole quality, efficient chip evacuation, and minimized tool wear.
A hole is considered deep when its depth exceeds 15 times its diameter. In PCB manufacturing, this means a 0.25 mm hole in a 3.75 mm thick panel meets the deep hole threshold. However, PCB panels also include entry and backup layers, increasing the total drilling depth. This extreme depth-to-diameter ratio makes positional accuracy critical—any misalignment can disrupt electrical conductivity and cause board failure.
Another challenge is tool deflection, where the drill bends under cutting forces, creating inaccurate, misaligned holes. Poor chip evacuation further complicates the process, leading to chip recutting, heat buildup, and tool breakage. Without proper strategies, deep hole drilling can result in defective boards, increased scrap rates, and costly rework.
Precision starts with accurate hole placement. Even slight deviations from the intended position can cause misaligned vias and signal integrity issues. To calculate true position, manufacturers use the formula:
True Position = √(x² + y²)
where x and y represent deviations from the intended hole center. To prevent positional errors, a pilot drill, like Kyocera’s Series 405, establishes a precise starting point, reducing tool deflection. Additionally, high-quality drills with near-perfect concentricity (<0.005 mm run-out) help maintain accuracy throughout the drilling process.
Beyond accuracy, hole quality determines the reliability of PCB electrical connections. Poor wall finish affects copper plating, leading to weak joints and conductivity issues. Flute geometry plays a crucial role—undercut designs minimize wall contact, reducing heat and friction, while optimized flute shapes ensure clean chip evacuation and smooth hole walls.
Kyocera’s hybrid drills maintain concentricity and produce clean, burr-free holes that enhance plating uniformity, improving the board’s overall performance. These tools are specifically designed to prevent common defects such as rough walls, misaligned holes, and poor plating adhesion.
Chip evacuation is a major concern in deep hole drilling. If chips are not efficiently removed, they can clog the hole, cause chip recutting, and generate excessive heat—shortening tool life and degrading hole quality. Effective chip evacuation relies on optimized flute geometry that promotes smooth material flow, preventing chip compaction and tool breakage.
Kyocera’s hybrid drills feature maximum material removal rates (MMR) and efficient chip shearing, eliminating bird-nesting and ensuring a clean drilling process. Proper speeds and feeds further enhance chip control, preventing excessive wear and maintaining productivity.
Deep hole drilling generates extreme cutting forces, leading to rapid tool wear if not properly managed. Excessive feed rates, poor heat dissipation, and suboptimal flute geometry contribute to premature tool failure. High-performance carbide grades and specialized coatings help extend tool life by reducing friction and heat buildup.
Even wear along the cutting edge indicates proper machining parameters, while uneven wear or sudden breakage often signals excessive cutting forces. Using a hybrid drill with reinforced core geometry minimizes stress on the tool, extending its lifespan and maintaining drilling consistency.
The best approach for deep hole drilling involves a two-step process. A pilot drill (Series 405) creates an accurate entry point, minimizing deflection and improving positional accuracy. Once established, a hybrid drill (Series 430) completes the hole with enhanced stability and chip evacuation.
Kyocera’s Series 430 Hybrid Drill features a “2 into 1” flute geometry, merging two flutes into one for better rigidity and chip control. This design allows for higher aspect ratio drilling while maintaining precision and tool longevity.
Deep hole drilling in PCBs requires more than just a sharp tool—it demands a well-planned strategy. By using Series 405 pilot drills to establish accurate hole placement and Series 430 hybrid drills for efficient chip evacuation and smooth hole walls, manufacturers can optimize their drilling process. This combination ensures precise, reliable holes with minimal tool wear, improving productivity and PCB performance.
By implementing these strategies, you’ll reduce tool wear, improve surface quality, and keep your processes running smoothly. The right approach isn’t about making dramatic changes all at once—it’s about incremental improvements that lead to big results over time.
Ready to optimize your PCB drilling process? Explore our selection of Kyocera solid carbide micro drills and hybrid drills to find the best fit for your operation. Locate a distributor near you, or reach out to our PCB machining experts—we’d love to help you solve your drilling challenges!
Q: What is considered a deep hole in PCB drilling?
A: A hole is classified as deep when its depth is at least 15 times its diameter. For example, a 0.25 mm hole in a 3.75 mm PCB panel meets the deep hole drilling threshold. Additional flute length is often required due to entry and backup layers in PCB panels.
Q: Why is positional accuracy so important in PCB drilling?
A: Even slight misalignment of holes can disrupt electrical conductivity, cause misaligned vias, and lead to board failure. The true position formula helps ensure precision by calculating the deviation from the intended hole center. Using a pilot drill, like Kyocera’s Series 405, minimizes drill wandering and enhances accuracy.
Q: How can I improve PCB drilling efficiency without sacrificing hole quality?
A: To balance efficiency and quality, focus on:
Q: What spindle speeds and feed rates are recommended for micro-drilling PCBs?
A: Micro-drilling PCBs requires high spindle speeds and precise feed control to prevent tool breakage and ensure clean hole quality. For holes under 0.50 mm in diameter, spindle speeds typically range from 80,000 to 150,000 RPM, with feed rates between 0.5 to 3.0 µm per revolution. Optimal settings depend on material type, hole size, and tool geometry. Running too slow can cause chip packing and burrs, while excessive feed rates increase tool stress and deflection. Always refer to manufacturer recommendations or consult a Kyocera PCB tooling expert for specific applications.
Q: What are the signs of improper drilling conditions in PCB manufacturing?
A: Some indicators of poor drilling conditions include burned hole walls, excessive burr formation, inconsistent hole diameters, and rapid tool failure. Each symptom suggests specific problems, such as incorrect feed rates, excessive deflection, or poor chip evacuation.
Q: What are the best methods for reducing burr formation in PCB holes?
A: Minimizing burrs in PCB drilling requires sharp carbide drills, optimized speeds and feeds, and proper support materials. Using entry and backup boards helps prevent fraying, while undercut drill geometries reduce exit burrs. Ensuring efficient chip evacuation with the right flute design and air/vacuum extraction prevents chip recutting, which can create secondary burrs. Additionally, coatings like TiAlN or DLC reduce friction and heat buildup for cleaner hole edges. If needed, mechanical brushing or chemical etching can remove residual burrs post-drilling.
Machinists require reliable solutions to tackle intricate tasks efficiently. Indexable tooling provides exceptional flexibility, quality, durability, and delivers high-performance results. Customize your tooling for specific tasks by choosing the ideal combination of inserts and holders to optimize performance.
Explore our SGS branded high-performance and versatile solid round tooling options. Our quality tooling not only ensures precision but also minimizes downtime, allowing for increased material removal per hour. Explore a range of options including end mills, drills, routers, countersinks, and more to find the perfect tools for your specific needs.
Get your machining fix with tips, articles, new innovations and more.
Contact
KYOCERA SGS Precision Tools, Inc.
(330) 686-5700
150 Marc Drive
Cuyahoga Falls, OH 44223
Products
Resources
