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.
IPC-DRM-SMT Explained: Surface Mount Solder Joint Inspection Guide
Surface mount technology dominates modern electronics assembly. Walk into any contract manufacturer today and you’ll see pick-and-place machines running at thousands of components per hour, reflow ovens processing boards continuously, and AOI systems scanning every joint. But when the AOI flags a potential defect, or when you need to train a new inspector on what constitutes an acceptable SMT solder joint, where do you turn?
That’s where IPC-DRM-SMT comes in. This 44-page training and reference guide puts surface mount solder joint acceptance criteria in a compact, visual format that works on the shop floor. It covers chip components, gull wing leads, J-leads, BGAs, and bottom termination components (QFN, LGA)—basically every SMT package type you’ll encounter in modern electronics manufacturing.
I’ve used IPC-DRM-SMT to train inspectors, settle accept/reject disputes, and correlate AOI programming with human visual inspection. The guide isn’t meant to replace IPC-A-610, but it makes the SMT sections of that standard accessible to operators and inspectors who need quick answers. This article covers what IPC-DRM-SMT includes, how to use it effectively, and why it’s become essential for SMT quality programs.
IPC-DRM-SMT stands for “Desk Reference Manual – Surface Mount Technology.” It’s a training and reference guide published by IPC that illustrates acceptance criteria for surface mount solder connections based on IPC-A-610, the industry’s primary standard for electronic assembly acceptability.
The guide uses computer-generated color illustrations to show dimensional acceptance criteria for each component type, plus high-quality photographs of actual solder defects and conditions. Each illustration clearly shows what acceptable and defective joints look like, with measurements and specifications for fillet heights, side overhang limits, and other critical dimensions.
IPC-DRM-SMT Key Information
Attribute
Details
Full Title
Surface Mount Solder Joint Evaluation Training & Reference Guide
Document Number
IPC-DRM-SMT
Current Revision
Revision G (aligned with IPC-A-610G) / QRG-SMT-H (aligned with IPC-A-610H)
Format
Spiral-bound, 5.5 x 8.5 inch (14 x 21.5 cm)
Page Count
Approximately 44 pages
Languages
English, German, Chinese, and others
Reference Standard
IPC-A-610 Rev G/H, Chapter 8
IPC-DRM-SMT Revision History
The guide is updated to align with new revisions of IPC-A-610:
Revision
Release
Aligned With
Key Updates
Rev B
2000
IPC-A-610B
Early SMT criteria
Rev C
2001
IPC-A-610C
Updated illustrations
Rev D
2005
IPC-A-610D
J-STD-001D references added
Rev E
2010
IPC-A-610E
Lead-free solder coverage expanded
Rev F
2015
IPC-A-610F
BGA and BTC sections added
Rev G
2017
IPC-A-610G
QFN/LGA criteria updated
Rev H (QRG-SMT)
2021
IPC-A-610H
Renamed to QRG series
Note: Starting with Rev H, IPC renamed the series from “DRM” (Desk Reference Manual) to “QRG” (Quick Reference Guide). The content and purpose remain the same—only the naming convention changed.
SMT Component Types Covered in IPC-DRM-SMT
One of the strengths of IPC-DRM-SMT is its comprehensive coverage of SMT package types. The guide addresses dimensional and visual acceptance criteria for five major component categories.
Component Types in IPC-DRM-SMT
Component Type
Examples
Key Criteria Covered
Chip Components
Resistors (0201-2512), Capacitors, MELFs
Side overhang, end overhang, fillet height, tombstoning
Gull Wing
SOIC, QFP, TQFP, TSOP
Heel fillet, toe fillet, side overhang, coplanarity
J-Lead
PLCC, SOJ
Heel fillet, toe fillet, solder on body
Ball Grid Array (BGA)
BGA, CSP, μBGA
Ball collapse, bridging, voiding, head-in-pillow
Bottom Termination (BTC)
QFN, DFN, LGA, SON
Side fillet, heel fillet, voiding, thermal pad
Chip Component Criteria
Chip components (rectangular passive components like resistors and capacitors) have specific dimensional requirements:
Key Dimensions for Chip Components:
Dimension
Description
Class 1
Class 2
Class 3
A – Side Overhang
Termination extends past land edge
≤ 50% W
≤ 50% W
≤ 25% W
B – End Overhang
Termination extends past land end
≤ 50% W
≤ 50% W
Not allowed
C – End Joint Width
Solder joint width at end
≥ 50% W
≥ 50% W
≥ 75% W
D – Side Joint Length
Solder fillet along side
Some evidence
Some evidence
≥ 25% L or 0.5mm
E – Maximum Fillet Height
Solder on top of termination
≤ G + H
≤ G + H
≤ G + H
F – Minimum Fillet Height
Minimum solder fillet
G
G
G + 25% H or 0.5mm
Where: W = component width, L = component length, G = solder thickness, H = termination height
Gull Wing Lead Criteria
Gull wing components (SOIC, QFP, etc.) have more complex solder joint geometry:
Key Dimensions for Gull Wing:
Dimension
Description
Class 1
Class 2
Class 3
A – Side Overhang
Lead extends past land side
≤ 50% W
≤ 50% W
≤ 25% W
B – Toe Overhang
Lead tip extends past land
Not specified
Not specified
Not specified
C – End Joint Width
Not applicable
—
—
—
D – Side Joint Length
Fillet along lead side
≥ 50% W
≥ 50% W
≥ 75% W
E – Maximum Fillet Height
Solder height limit
G + L
G + L
G + L
F – Heel Fillet Height
Minimum heel fillet
G
G
G + 25% T or 0.5mm
Where: W = lead width, L = lead length, G = solder thickness, T = lead thickness
BGA and Area Array Criteria
BGAs and area array packages present unique inspection challenges because joints are hidden under the component. IPC-DRM-SMT addresses visual and X-ray inspection criteria:
BGA Acceptance Criteria:
Criterion
Class 1
Class 2
Class 3
Ball Collapse
Even collapse across package
Even collapse across package
Even collapse across package
Bridging
Defect
Defect
Defect
Voids (per joint)
≤ 25% of ball volume
≤ 25% of ball volume
≤ 25% of ball volume
Missing Balls
Defect
Defect
Defect
Head-in-Pillow
Defect
Defect
Defect
Bottom Termination Component (QFN/LGA) Criteria
BTCs have become increasingly common but present inspection challenges because terminations are under the component. IPC-DRM-SMT Rev F and later include specific BTC criteria:
BTC Acceptance Criteria:
Criterion
Description
Class 1
Class 2
Class 3
Side Fillet
Visible fillet on component edge
Preferred
Preferred
Required where visible
Heel Fillet
Fillet at inner edge of termination
Evidence required
Evidence required
Required
Thermal Pad Voiding
Voids under thermal pad
≤ 50%
≤ 25%
≤ 25%
Bridging
Between adjacent terminations
Defect
Defect
Defect
IPC-DRM-SMT Dimensional Criteria Explained
Understanding the lettered dimensions (A, B, C, D, E, F) is essential for using IPC-DRM-SMT effectively. These dimensions are consistent across component types but with different requirements.
Universal Dimension Definitions
Dimension
Name
Measures
A
Side Overhang
How far component extends past land edge (lateral)
B
Toe/End Overhang
How far component end extends past land (longitudinal)
C
End Joint Width
Width of solder joint at component end
D
Side Joint Length
Length of solder fillet along component side
E
Maximum Fillet Height
Upper limit on solder height
F
Minimum Fillet Height
Lower limit on solder height (ensures adequate joint)
G
Solder Thickness
Thickness of solder between surfaces
H
Termination Height
Height of component termination
W
Width
Component or lead width
L
Length
Component or lead length
T
Lead Thickness
Thickness of component lead
Why Dimensional Criteria Matter
Each dimension addresses a specific reliability concern:
Side Overhang (A): Excessive side overhang can cause bridging to adjacent components or reduce joint area. Class 3 requires tighter control (25% vs. 50%) because reliability demands more precise placement.
End Overhang (B): Excessive end overhang indicates placement error and may not leave enough land area for proper solder joint formation. Class 3 doesn’t allow any end overhang.
Fillet Height (F): Minimum fillet height ensures adequate solder volume for mechanical strength. Too little solder weakens the joint; too much can mask defects or cause shorts.
Side Joint Length (D): Ensures solder wets along the component side, providing visible evidence of proper joint formation and adequate strength.
The guide provides photographs and illustrations of common SMT defects, making it easier to identify problems during visual or AOI inspection.
SMT Solder Defects Summary
Defect
Description
Visual Indicators
Affected Components
Tombstoning
Component stands on one end
One termination lifted, vertical component
Chip components
Billboarding
Component shifts to vertical position
Component standing on edge
Chip components
Insufficient Solder
Not enough solder volume
No visible fillet, exposed termination
All SMT
Excess Solder
Too much solder
Convex fillet, obscured lead outline
All SMT
Solder Bridging
Unintended connection
Solder spans to adjacent land/lead
All SMT
Nonwetting
Solder doesn’t adhere
Visible basis metal, beaded solder
All SMT
Dewetting
Solder recedes after wetting
Irregular coverage, exposed areas
All SMT
Cold Joint
Disturbed/improperly formed
Grainy, dull, irregular surface
All SMT
Head-in-Pillow
BGA ball doesn’t collapse properly
Partial connection, visible gap in X-ray
BGA
Voiding
Cavities in solder joint
Visible holes or X-ray dark spots
BGA, BTC, large thermal pads
Solder Balls
Loose spheres of solder
Small balls on board surface
All SMT (especially after reflow)
Tombstoning and Billboarding
These defects are unique to chip components and occur during reflow when solder wetting forces are unbalanced:
Tombstoning: One end of the component lifts completely off the pad, standing the component vertical. This is always a defect for all classes.
Billboarding: The component rotates to stand on its edge (side). This is also a defect for all classes.
Causes include:
Unequal pad sizes
Unequal solder paste deposits
Uneven heating during reflow
Component placement offset
Head-in-Pillow (BGA Defect)
Head-in-pillow (HIP) is a BGA defect where the solder ball and paste don’t properly coalesce during reflow. The ball appears to rest “on” the solder rather than fully merging with it. IPC-DRM-SMT shows X-ray images of this defect.
Characteristics:
Often invisible to visual inspection
Appears as partial collapse in X-ray
May show intermittent electrical connection
Defect for all classes
Lead-Free vs. Tin-Lead Solder Appearance
IPC-DRM-SMT addresses the visual differences between lead-free and tin-lead solder joints—critical knowledge for inspectors:
Characteristic
Tin-Lead Solder
Lead-Free Solder
Surface Finish
Bright, shiny
May be dull, matte, or grainy
Contact Angle
Generally lower (flatter fillet)
May be higher (steeper fillet)
Surface Texture
Smooth
May show graininess or texture
Color
Silver-bright
Slightly different hue possible
Important: Surface appearance alone doesn’t determine acceptability. A dull lead-free joint can be perfectly acceptable if it meets dimensional criteria and shows proper wetting.
IPC-DRM-SMT vs. IPC-DRM-PTH: Which Do You Need?
IPC publishes separate guides for surface mount and through-hole inspection. Understanding when to use each is important for comprehensive training programs.
Comparison: IPC-DRM-SMT vs. IPC-DRM-PTH
Aspect
IPC-DRM-SMT
IPC-DRM-PTH
Full Name
Surface Mount Solder Joint Evaluation
Through-Hole Solder Joint Evaluation
Focus
SMT component solder joints
Plated through-hole connections
Page Count
~44 pages
~30 pages
Component Types
Chip, gull wing, J-lead, BGA, BTC
Axial, radial, DIP, connectors
Key Criteria
Fillet dimensions, side overhang
Barrel fill, circumferential wetting
Defect Focus
Tombstoning, bridging, HIP
Cold joints, insufficient fill
Reference Standard
IPC-A-610 Chapter 8
IPC-A-610 Chapter 7
Typical Use
Reflow soldering inspection
Wave/hand soldering inspection
When to Use Each Guide
Use IPC-DRM-SMT when:
Inspecting reflow-soldered assemblies
Evaluating chip components, QFP, SOIC, BGA, QFN
Training operators on SMT placement quality
Correlating AOI defect detection with acceptance criteria
Mixed technology boards (for the SMT portion)
Use IPC-DRM-PTH when:
Inspecting wave-soldered assemblies
Evaluating hand-soldered through-hole connections
Training operators on PTH component assembly
Mixed technology boards (for the PTH portion)
Use Both when:
Mixed technology assembly operations
Comprehensive inspector training programs
Quality systems covering all assembly types
How IPC-DRM-SMT Relates to IPC-A-610
IPC-DRM-SMT doesn’t replace IPC-A-610—it supplements it by providing quick visual reference to SMT-specific criteria from Chapter 8 of the standard.
Document Relationships
Document
Purpose
Scope
IPC-A-610
Complete acceptance standard
All assembly types, all criteria
IPC-DRM-SMT
Quick reference for SMT
Surface mount joints only
IPC-DRM-PTH
Quick reference for PTH
Through-hole joints only
J-STD-001
Process requirements
Materials and methods
Cross-References in IPC-DRM-SMT
Each acceptance criterion in IPC-DRM-SMT includes references to corresponding sections in IPC-A-610. For example:
This cross-referencing allows inspectors to quickly find more detailed information when needed.
Implementing IPC-DRM-SMT in Your Operation
Training Applications
IPC-DRM-SMT is designed as a training aid. Here’s how to use it effectively:
Initial Inspector Training:
Use illustrations to explain SMT joint anatomy
Walk through dimensional criteria for each component type
Compare target, acceptable, and defect conditions
Practice with actual samples and photographs
AOI Correlation:
Use IPC-DRM-SMT criteria to program AOI acceptance limits
Verify AOI calls against visual inspection using the guide
Train operators to understand why AOI flags specific conditions
Ongoing Reference:
Keep copies at inspection and rework stations
Use for accept/reject dispute resolution
Reference during quality audits and customer discussions
Training Program Structure
Training Element
Duration
Content
Introduction
30 min
SMT joint anatomy, class definitions
Chip Components
1 hour
Dimensional criteria, tombstoning, bridging
Leaded SMT
1.5 hours
Gull wing, J-lead criteria, fillet requirements
Area Arrays
1.5 hours
BGA, QFN, voiding, head-in-pillow
Defect Recognition
2 hours
Study photographs, practice identification
Hands-On Practice
2-4 hours
Inspect actual samples, compare to guide
Assessment
1 hour
Written and practical evaluation
Where to Purchase IPC-DRM-SMT
Official Sources
Source
URL
Notes
IPC Store
shop.ipc.org
Official source, PDF and print available
EPTAC
eptac.com
Authorized distributor
BEST Inc.
solder.net
Training provider, sells materials
Blackfox
blackfox.com
Training provider, sells materials
Pricing (Approximate)
Format
IPC Member
Non-Member
Print (spiral-bound)
$38
$47
PDF (single-user)
$38
$47
Site License
Contact IPC
Contact IPC
Related IPC Training Materials
Document
Description
IPC-DRM-PTH
Through-Hole Solder Joint Evaluation Guide
IPC-DRM-18
Component Identification Training Guide
IPC-A-610
Complete Acceptability Standard
J-STD-001
Soldering Requirements Standard
IPC-7095
BGA Design and Assembly Guide
IPC-7093
BTC Design and Assembly Guide
IPC-DRM-SMT Resources and Downloads
IPC Official Resources
IPC Store: shop.ipc.org/ipc-drm-smt
Free Demo PDF: Available on IPC Store (limited pages)
IPC Training Programs: ipc.org/training
IPC-A-610 Certification: ipc.org/certification
Training Providers Offering IPC-DRM-SMT Content
Provider
Website
Services
EPTAC Corporation
eptac.com
IPC certification, hands-on training
BEST Inc.
solder.net
Soldering training, materials
STI Electronics
stiusa.com
IPC certification programs
Blackfox Training
blackfox.com
Online and in-person training
ACI Technologies
aciusa.org
IPC training, consulting
Related IPC Certifications
Certification
Description
IPC-A-610 CIS
Certified IPC Specialist for Assembly Acceptability
IPC-A-610 CIT
Certified IPC Trainer for Assembly Acceptability
J-STD-001 CIS
Certified IPC Specialist for Soldering
J-STD-001 CIT
Certified IPC Trainer for Soldering
Frequently Asked Questions About IPC-DRM-SMT
Does IPC-DRM-SMT cover BGA and QFN inspection?
Yes, starting with Revision F (2015), IPC-DRM-SMT includes dedicated sections for Ball Grid Arrays (BGAs) and Bottom Termination Components (BTCs) like QFN and LGA packages. These sections address the unique inspection challenges of these component types, including X-ray inspection criteria for BGAs and side fillet requirements for QFNs. If you’re working with area array packages, make sure you have Rev F or later—earlier revisions don’t include this coverage.
Is IPC-DRM-SMT sufficient for inspector training, or do I need IPC-A-610?
IPC-DRM-SMT is a training aid and quick reference, not a replacement for IPC-A-610. For comprehensive inspector training, you need both. IPC-A-610 provides the complete acceptance criteria with full context and additional requirements that IPC-DRM-SMT doesn’t cover (handling, cleanliness, marking, etc.). Use IPC-DRM-SMT for focused SMT solder joint training and shop floor reference, but ensure inspectors also receive IPC-A-610 training for complete knowledge. Many organizations use IPC-DRM-SMT for operator-level training and IPC-A-610 for inspector certification.
How do I correlate AOI programming with IPC-DRM-SMT criteria?
IPC-DRM-SMT dimensional criteria can directly inform AOI programming. The dimensions (A, B, C, D, E, F) for each component type translate to measurable parameters that AOI systems evaluate. When programming AOI, use IPC-DRM-SMT as your reference for acceptable limits—for example, setting side overhang (Dimension A) limits at 50% of component width for Class 2 or 25% for Class 3. When AOI flags a defect, use IPC-DRM-SMT to verify whether the condition actually fails acceptance criteria. This correlation ensures your AOI programming aligns with industry standards.
What’s the difference between IPC-DRM-SMT and IPC-QRG-SMT?
They’re the same product with different naming. Starting with the revision aligned to IPC-A-610H, IPC renamed the series from “DRM” (Desk Reference Manual) to “QRG” (Quick Reference Guide). The content, format, and purpose remain unchanged. If you’re purchasing the current version, you may see it listed as IPC-QRG-SMT-H. Both DRM and QRG designations refer to the same training and reference guide product line. Don’t be confused by the name change—it’s the same valuable resource.
Can I use IPC-DRM-SMT criteria for lead-free assemblies?
Absolutely. IPC-DRM-SMT explicitly addresses lead-free solder appearance and criteria. The guide notes that lead-free solder joints may appear duller, have grainier surfaces, and exhibit higher contact angles than tin-lead joints—without these characteristics being defects. The dimensional acceptance criteria (fillet heights, overhang limits, etc.) are the same regardless of solder alloy. What differs is visual appearance, and IPC-DRM-SMT helps inspectors understand these differences so they don’t reject acceptable lead-free joints based on appearance alone.
Conclusion
IPC-DRM-SMT serves an essential role in SMT quality programs. It takes the surface mount acceptance criteria from IPC-A-610 Chapter 8 and presents them in a visual, accessible format that works on the shop floor, in the training room, and during quality discussions.
The guide’s strength is its comprehensive component coverage combined with clear dimensional illustrations. Whether you’re inspecting chip resistors, QFP packages, BGAs, or QFN devices, IPC-DRM-SMT provides the acceptance criteria in a format that inspectors can quickly reference and apply.
For operations running SMT assembly—which is essentially every electronics manufacturer today—IPC-DRM-SMT should be part of your quality toolkit. The investment is minimal (under $50 per copy), and the payback comes through more consistent inspection decisions, faster training, and fewer disputes about what constitutes an acceptable solder joint.
If you’re responsible for SMT quality, obtain the current revision (QRG-SMT-H for IPC-A-610H alignment, or DRM-SMT-G for IPC-A-610G) and integrate it into your training and inspection programs. Combined with IPC-DRM-PTH for mixed technology operations, you’ll have the visual reference tools needed to support a comprehensive solder joint quality program.
The bottom line: IPC-DRM-SMT makes IPC-A-610 SMT criteria practical and usable. That’s exactly what inspectors and operators need when they’re making accept/reject decisions on the line.
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.
