Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.
Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.
Notes: For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.
If you’ve ever pulled a panel off the drilling machine only to find rough hole walls, excessive burrs, or nail heading on your inner layers, you know how frustrating drilling defects can be. What seems like a straightforward mechanical operation—spinning a carbide bit through fiberglass laminate—turns out to be one of the most critical processes in PCB fabrication. Get it wrong, and you’ll see the consequences in plating voids, poor barrel reliability, and rejected boards.
That’s exactly why IPC-DR-572 exists. This compact but essential standard provides the drilling guidelines that separate shops producing consistently high-quality holes from those constantly fighting defects. After years of troubleshooting drilling issues in multilayer production, I can tell you this document addresses the real problems fabricators face every day.
What Is IPC-DR-572?
IPC-DR-572, officially titled “Drilling Guidelines for Printed Boards,” is an IPC standard that provides comprehensive guidance for generating high-quality holes in printed circuit boards made from various materials. Originally published in 1988, the standard was revised in 1998 and again with the current Revision A released in March 2007.
Despite being only 12 pages, IPC-DR-572 packs essential information covering drill bit selection and maintenance, tooling materials, stack drilling considerations, drilling machine parameters, drilling operations, hole quality criteria, and troubleshooting guidance. The standard addresses drilling challenges across different PCB materials including FR-4, high-Tg laminates, polyimide, PTFE, and metal-core substrates.
IPC-DR-572 targets drill operators, process engineers, and quality personnel in PCB fabrication facilities. Whether you’re setting up a new drilling operation or troubleshooting yield issues on an established line, this standard provides the technical foundation for consistent results.
Why PCB Drilling Quality Matters
Drilling is often called the most critical mechanical process in PCB fabrication, and for good reason. Every plated through-hole starts as a drilled hole, and the quality of that hole directly affects plating adhesion, barrel integrity, and long-term reliability. Industry data suggests drilling-related defects account for 15-25% of PCB fabrication rejects in typical operations.
The Challenge of Drilling Composite Materials
PCB laminates present unique drilling challenges because they combine multiple materials with very different properties:
Material Layer
Characteristics
Drilling Challenge
Copper foil
Ductile metal, 0.5-2 oz
Burr formation, smearing
Glass fabric
Abrasive, hard fibers
Rapid tool wear
Epoxy resin
Thermoplastic at temperature
Smear, nail heading
Prepreg
Partially cured resin
Delamination risk
The glass fibers in FR-4 are extremely abrasive—they wear carbide drill bits at rates that would be unacceptable in metal machining. Meanwhile, the epoxy resin can soften and smear at elevated temperatures, coating hole walls and inner layer connections. Balancing speed, tool life, and hole quality requires the systematic approach that IPC-DR-572 provides.
Drill Bit Guidelines in IPC-DR-572
The drill bit is the heart of the drilling operation, and IPC-DR-572 provides detailed guidance on selection, inspection, and maintenance.
Key Drill Bit Geometries
IPC-DR-572 defines critical drill bit geometries that affect hole quality:
Geometry Parameter
Typical Value
Impact on Drilling
Point angle
130-140°
Entry/exit quality, thrust force
Helix angle
28-32°
Chip evacuation efficiency
Web thickness
15-20% of diameter
Strength vs. chip clearance
Flute length
2-3x diameter
Stack height capability
Primary relief
12-18°
Cutting efficiency
Chisel edge
Minimized
Centering accuracy
Standard PCB drill bits use a 1/8″ (3.175mm) shank regardless of cutting diameter, allowing quick tool changes in high-speed spindles. For micro-drilling below 0.3mm diameter, specialized geometries with modified point angles improve centering and reduce breakage.
Drill Bit Wear and Replacement
Tool wear is inevitable when drilling abrasive glass-reinforced laminates. IPC-DR-572 provides guidance on monitoring wear and establishing replacement criteria:
Application
Typical Hits Per Bit
Regrind Allowance
Double-sided FR-4
3,000-3,500
2-3 regrinds
Multilayer FR-4
500-1,000
2-3 regrinds
High-Tg laminates
300-700
1-2 regrinds
PTFE/Ceramic
200-500
Limited
After each regrind, the effective flute length decreases, limiting stack height capability. IPC-DR-572 recommends tracking cumulative hits and regrinds to prevent quality degradation from over-used tooling.
Drill Bit Inspection
Regular inspection catches problems before they create defects:
Inspection Point
Method
Reject Criteria
Point condition
Microscope 20-50x
Chipping, wear > 0.2mm
Flute contamination
Visual
Debris buildup
Shank damage
Visual
Scratches, corrosion
Runout
Indicator
> 0.01mm TIR
Worn bits with damaged cutting edges produce rough hole walls and increased thrust force, leading to nail heading and delamination. The cost of a new drill bit is trivial compared to scrapped panels.
Drilling Parameters and Optimization
IPC-DR-572 addresses the key parameters that control drilling quality: spindle speed, feed rate, and their combination into chip load.
Spindle Speed Guidelines
PCB drilling uses much higher spindle speeds than conventional metal machining:
Drill Diameter
Recommended RPM
Surface Speed
0.2-0.3 mm
80,000-120,000
50-110 SFM
0.3-0.5 mm
60,000-100,000
60-100 SFM
0.5-1.0 mm
40,000-80,000
65-130 SFM
1.0-2.0 mm
30,000-60,000
95-190 SFM
> 2.0 mm
20,000-40,000
125-250 SFM
Higher speeds are required for smaller diameters to maintain adequate surface speed at the cutting edge. Modern CNC drilling machines with air-bearing spindles routinely achieve 100,000+ RPM for microvia drilling.
Feed Rate and Chip Load
Feed rate determines how fast the drill advances through the material. The critical parameter is chip load—the amount of material removed per flute per revolution:
Chip Load = Feed Rate (IPM) ÷ (RPM × Number of Flutes)
Material
Recommended Chip Load
Standard FR-4
0.001-0.002 in/rev
High-Tg FR-4
0.0008-0.0015 in/rev
Polyimide
0.0008-0.0012 in/rev
PTFE
0.0015-0.0025 in/rev
Chip load that’s too high causes excessive tool stress and rough holes. Chip load that’s too low generates excessive heat because the tool rubs rather than cuts, causing resin smear and accelerated wear. IPC-DR-572 emphasizes finding the optimal balance for each material and drill size combination.
Retract Rate Considerations
The retract rate—how fast the drill withdraws after completing the hole—affects both cycle time and hole quality. Rapid retraction can pull debris back into the hole or create vacuum effects that stress the laminate. IPC-DR-572 recommends retract rates 1.5-2x the infeed rate for optimal chip evacuation without quality compromise.
Entry and Backup Materials
Proper tooling materials above and below the drilling stack are essential for hole quality. IPC-DR-572 provides guidance on both entry and backup materials.
Entry Materials
Entry material serves multiple functions: centering the drill, preventing top-side burrs, and lubricating the cut.
Entry Material
Thickness
Application
Aluminum sheet
0.15-0.20 mm
Standard drilling
Aluminum/resin composite
0.20-0.25 mm
High-speed drilling
Phenolic-backed aluminum
0.25-0.35 mm
Controlled-depth drilling
Aluminum entry material should be free of scratches and contamination. Surface defects transfer to the drilled panel, causing registration issues and cosmetic defects.
Backup Materials
Backup material supports the exit side of the drilling stack, preventing exit burrs and breakout:
Backup Material
Thickness
Characteristics
Phenolic
1.5-3.0 mm
Standard, economical
Melamine
1.5-2.5 mm
Harder, longer life
Composite
2.0-3.0 mm
Specialized applications
Wood fiber
2.5-4.0 mm
Large holes
Backup material must be flat and free of embedded debris from previous use. IPC-DR-572 recommends limiting backup reuse based on visible wear patterns and hole quality monitoring.
Stack Drilling Guidelines
Stack drilling—drilling multiple panels simultaneously—is essential for production efficiency, but improper stacking causes quality problems. IPC-DR-572 provides stack height guidelines based on drill diameter.
Stack Height Rules
Drill Diameter
Maximum Stack Height
Typical Panel Count
< 0.5 mm
2x diameter
1-2 thin panels
0.5-1.0 mm
3x diameter
2-3 panels
1.0-2.0 mm
4-5x diameter
3-4 panels
> 2.0 mm
5-6x diameter
4-6 panels
Exceeding recommended stack heights causes drill wander, rough holes in bottom panels, and increased breakage risk. The flute length must exceed stack height plus entry and backup material thickness.
Aspect Ratio Considerations
For deep holes in thick stacks, aspect ratio (depth-to-diameter) becomes critical:
Aspect Ratio
Drilling Consideration
< 6:1
Standard parameters
6:1 – 10:1
Reduced feed rate, peck drilling may help
> 10:1
Specialized techniques required
High aspect ratio holes are prone to roughness in the lower portion and chip packing that can break drill bits. IPC-DR-572 recommends reducing chip load by 20-30% for aspect ratios exceeding 10:1.
Hole Quality Criteria
IPC-DR-572 defines what constitutes a “good hole” and the defects that indicate process problems.
Good Hole Characteristics
Quality Attribute
Requirement
Hole wall roughness
Smooth, suitable for plating
Burrs
Minimal, removable by standard deburring
Nail heading
Absent or minimal
Positional accuracy
Within specified tolerance
Hole size
Within specified tolerance
Roundness
No significant ovality
Hole wall roughness directly affects plating adhesion and barrel reliability. Rough walls may accept copper during plating but fail under thermal stress when the plating separates from the peaks and valleys of the rough surface.
Common Drilling Defects
IPC-DR-572 addresses the most common drilling defects and their root causes:
Defect
Description
Primary Causes
Rough hole walls
Visible texture, poor plating
Worn bit, wrong parameters, material issue
Burrs
Copper protrusion at entry/exit
Dull bit, wrong entry/backup, excess speed
Nail heading
Resin smear over inner layers
Excess heat, dull bit, wrong feed rate
Hole size variation
Over/undersized holes
Bit wear, spindle runout, wrong bit
Positional error
Hole location offset
Registration error, drill wander
Drill breakage
Broken bit in hole
Excessive stack, worn bit, chip packing
Understanding these defects and their causes enables systematic troubleshooting rather than trial-and-error parameter adjustments.
IPC-DR-572 addresses drilling machine capabilities that affect hole quality.
Critical Machine Parameters
Parameter
Requirement
Impact
Spindle runout
< 0.005-0.010 mm
Hole size accuracy
Spindle speed accuracy
±2% of set point
Consistent cut quality
Z-axis positioning
±0.025 mm
Depth control
Table flatness
< 0.05 mm over work area
Consistent hole depth
Pressure foot force
Adjustable, consistent
Stack stability
Vacuum systems for chip evacuation should maintain consistent airflow through the drilling area. Poor chip evacuation leads to chip packing, overheating, and accelerated tool wear.
IPC-DR-572 and Related Standards
Standard
Focus
Relationship to IPC-DR-572
IPC-DR-570
Carbide drill specifications
Drill bit requirements
IPC-6012
Rigid board qualification
Hole quality acceptance
IPC-6013
Flex board qualification
Flexible material drilling
IPC-PE-740
Troubleshooting handbook
Expanded troubleshooting
IPC-9121
Fabrication troubleshooting
Process problem solving
IPC-DR-572 focuses specifically on the drilling operation, while these related standards address broader qualification requirements and troubleshooting across all fabrication processes.
Who Needs IPC-DR-572?
Drill Operators
Operators need IPC-DR-572 for proper machine setup, parameter selection, and quality monitoring. Understanding the “why” behind drilling parameters helps operators catch problems before they create scrap.
Process Engineers
Engineers developing drilling processes use IPC-DR-572 for parameter optimization, troubleshooting, and continuous improvement. The standard provides a framework for systematic process development.
Quality Engineers
Quality personnel reference IPC-DR-572 when evaluating hole quality and investigating drilling-related rejects. Understanding drilling fundamentals enables effective root cause analysis.
How to Access IPC-DR-572
Source
Format
Price Range
IPC Official Store (shop.ipc.org)
PDF (DRM protected)
$62-75
ANSI Webstore
PDF
$65-80
Techstreet
PDF
$60-75
GlobalSpec
Reference access
Varies
IPC-DR-572A (March 2007) is the current revision. At only 12 pages, it’s one of the more affordable IPC standards while providing essential guidance for a critical process.
Frequently Asked Questions About IPC-DR-572
How many holes can a drill bit produce before replacement?
IPC-DR-572 provides general guidelines: 3,000-3,500 hits for standard FR-4 double-sided boards, and 500-1,000 hits for multilayer boards. However, actual tool life depends on material hardness, stack height, and hole quality requirements. High-reliability applications may require more frequent replacement. The key is monitoring hole quality and replacing bits before defects appear—not running tools until they fail catastrophically.
What spindle speed should I use for PCB drilling?
Spindle speed depends primarily on drill diameter. Smaller holes require higher speeds to maintain adequate surface speed at the cutting edge. For common 0.3-0.5mm holes in FR-4, speeds of 60,000-100,000 RPM are typical. Larger holes (1.0mm+) use 30,000-60,000 RPM. IPC-DR-572 emphasizes that speed and feed rate must be optimized together—changing one without adjusting the other can cause quality problems.
How do I prevent nail heading on inner layers?
Nail heading (resin smear) results from excessive heat softening the epoxy resin during drilling. Prevention strategies include using sharp drill bits and replacing them before wear causes rubbing, reducing chip load if heat marks appear, ensuring effective vacuum chip evacuation, and verifying spindle speed isn’t excessive for the drill diameter. If nail heading persists, desmear processes can remove smear before plating, but prevention is always preferable.
What causes drill breakage and how do I prevent it?
Drill breakage typically results from excessive stack height exceeding the bit’s capability, chip packing in the flutes due to poor evacuation, worn bits with weakened cutting edges, or lateral forces from misaligned stacks or improper fixturing. Prevention includes following stack height guidelines (typically 2-6x drill diameter depending on size), maintaining vacuum systems, replacing bits per schedule, and ensuring proper stack alignment. Broken bits lodged in holes require careful removal to avoid damaging the panel.
How does IPC-DR-572 relate to IPC-6012 acceptance criteria?
IPC-DR-572 provides process guidelines to produce good holes, while IPC-6012 defines acceptance criteria for the finished product. Meeting IPC-6012 requirements for hole quality—wall roughness, copper coverage, barrel integrity—starts with following IPC-DR-572 drilling guidelines. When drilling processes are properly controlled per IPC-DR-572, meeting IPC-6012 hole quality requirements becomes straightforward.
Conclusion: Mastering PCB Drilling with IPC-DR-572
Drilling may seem like a simple mechanical operation, but consistent hole quality requires systematic process control. The difference between a shop that consistently produces excellent holes and one fighting constant quality issues often comes down to following the fundamentals that IPC-DR-572 documents.
Key takeaways for drilling success:
Manage your tooling—drill bits are consumables; replace them before they cause problems
Optimize parameters together—speed and feed rate interact; changing one requires evaluating the other
Maintain your equipment—spindle runout and vacuum efficiency directly affect hole quality
Monitor and respond—catch quality trends early before they become yield problems
The 12 pages of IPC-DR-572 represent decades of industry experience with PCB drilling. Engineers who internalize these guidelines spend less time troubleshooting and more time producing quality product.
Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.
Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.
Notes: For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.
