A DIP assembly line is used to install and solder through-hole components on printed circuit boards.
Although the term DIP originally refers to Dual In-line Package, many PCB assembly factories use “DIP line” as a broader production term for THT, or Through-Hole Technology, assembly.
Typical THT components include:
- Connectors
- Terminal blocks
- Relays
- Transformers
- Switches
- Large capacitors
- Pin headers
- Selected power components
- Electromechanical devices
Unlike a standard SMT line, where components are automatically placed on the PCB surface and soldered in a reflow oven, a DIP/THT line may involve a combination of manual insertion, automatic PCB handling, wave soldering, selective soldering, inspection, and testing.
So, what equipment is required for a DIP assembly line?
The answer depends on the PCB, BOM, production volume, product mix, soldering method, and required automation level.
A typical complete line can include:
PCB Loader → Component Preparation → DIP/THT Insertion → Inspection Conveyor → Fluxing → Preheating → Wave Soldering → Cooling → PCB Unloader → Inspection → Testing
What Equipment Is Required for a DIP Assembly Line?
This guide explains the main equipment used in a DIP production line and how manufacturers can select the correct configuration.
PCB Loader
A PCB loader feeds boards into the production line.
In a low-volume factory, operators may load PCBs manually.
For medium- or high-volume production, an automatic loader can improve material flow and reduce repetitive handling.
Important selection factors include:
- PCB dimensions
- Panel size
- PCB thickness
- Board weight
- Magazine size
- Conveyor height
- Production direction
The loader should be compatible with downstream conveyors and insertion stations.
PCB Conveyors
Conveyors are an important part of a complete DIP assembly line because manual insertion typically requires more workstation space than SMT placement.
Conveyors can be used for:
- PCB transportation
- Manual component insertion
- Inspection
- Buffering
- Connecting machines
- Work-in-process control
Possible configurations include:
- Standard transfer conveyors
- Insertion conveyors
- Inspection conveyors
- Buffer conveyors
- Adjustable-width conveyors
A well-designed conveyor system can reduce unnecessary PCB handling and improve operator workflow.
THT Component Preparation Equipment
Many through-hole components cannot be inserted directly from their original packaging.
Before insertion, leads may need to be:
- Cut
- Formed
- Bent
- Straightened
- Sorted
- Oriented
- Prepared to a specified length
Common supporting equipment may include:
- Lead cutting machines
- Lead forming machines
- Resistor forming machines
- Capacitor lead processing machines
- Component preparation machines
Component preparation is especially important in manual DIP assembly because poor preparation can slow down every downstream insertion operator.
Component Material Racks and Kitting Systems
Although they are not always considered major machines, material racks and kitting systems can significantly influence production efficiency.
A good workstation should help operators quickly identify:
- Component part number
- PCB position
- Polarity
- Orientation
- Required quantity
Factories may use:
- Component bins
- Material carts
- Pick-to-light systems
- Kitting trays
- Barcode systems
The objective is to reduce time spent searching for components.
Manual DIP Insertion Workstations
Manual insertion remains widely used because through-hole components can vary greatly in:
- Shape
- Size
- Lead configuration
- Packaging
- Mechanical structure
A manual insertion station typically includes:
- Insertion conveyor
- Component racks
- Work instructions
- Lighting
- ESD protection
- Fixtures where required
Manual insertion is especially suitable for:
- High-mix production
- Low- or medium-volume manufacturing
- Frequent product changes
- Complex THT components
The number of operators should be determined by actual cycle-time analysis.
Semi-Automatic THT Insertion Equipment
Semi-automatic equipment can assist operators with selected through-hole components or repetitive tasks.
It may help improve:
- Insertion speed
- Component positioning
- Operator ergonomics
- Process repeatability
This can provide a useful middle ground between fully manual and fully automatic production.
For many EMS factories, partial automation can offer better ROI than automating every component.
Automatic THT Insertion Machine
Automatic insertion equipment can be considered for suitable components and higher-volume production.
The machine may automatically:
- Feed components
- Cut or form leads
- Position components
- Insert them into the PCB
Automatic insertion becomes more attractive when:
- Production volume is high
- Product demand is stable
- Component types are standardized
- Packaging supports automatic feeding
- The same components repeat across many boards
However, not every relay, connector, transformer, or irregular component can be efficiently automated.
For this reason, the BOM should always be reviewed before selecting automatic insertion equipment.
Pre-Solder Inspection Conveyor
After component insertion, the board should usually be checked before entering the soldering process.
An inspection conveyor provides a dedicated area to identify:
- Missing components
- Wrong components
- Incorrect polarity
- Incorrect orientation
- Bent leads
- Improper insertion depth
- Component misalignment
This stage can reduce the cost of downstream rework.
Repairing an incorrectly inserted component before wave soldering is generally easier than removing and replacing it after soldering.
Fluxing System
Before wave soldering, flux is applied to the solder side of the PCB.
Many modern wave soldering machines include an integrated fluxing system.
A common configuration is spray fluxing.
Important parameters include:
- Flux type
- Application quantity
- Spray width
- Spray uniformity
- Conveyor speed
Excessive flux does not automatically improve quality.
The goal is stable and controlled coverage.
Preheating System
After fluxing, the PCB passes through a preheating section.
Preheating helps prepare the assembly for soldering.
It can support:
- Flux activation
- Gradual PCB temperature increase
- Reduced thermal shock
- More stable soldering conditions
The required profile depends on:
- PCB thickness
- Copper distribution
- Component thermal mass
- Flux chemistry
- Solder alloy
- Conveyor speed
Wave soldering equipment may use different preheating technologies depending on the machine configuration.
Wave Soldering Machine
For many DIP production lines, the wave soldering machine is the central soldering equipment.
The PCB passes over a controlled wave of molten solder, allowing multiple through-hole joints to be soldered during one continuous process.
A wave soldering machine commonly includes:
- Fluxing section
- Preheating zones
- Solder pot
- Wave system
- Conveyor
- Control system
- Cooling section
Important selection factors include:
- Maximum PCB width
- Conveyor speed
- Preheating capacity
- Solder pot configuration
- Process control functions
- Production capacity
- Factory utilities
The machine should be chosen according to the actual PCB rather than only the rated maximum speed.
Selective Soldering Machine
Not every DIP assembly line requires wave soldering.
For some mixed SMT/THT products, selective soldering may be more suitable.
A selective soldering machine applies solder only to programmed through-hole joints or defined areas.
It is particularly useful when:
- Only a small number of THT joints need soldering
- Bottom-side SMT components are present
- Certain areas must avoid broad solder contact
- Localized process control is important
A typical system can include:
- Selective fluxing
- Preheating
- Programmable solder nozzle
- PCB handling
- Process control
Factories with a wide product range may use both wave and selective soldering for different PCB models.
Cooling Equipment
After wave or selective soldering, the PCB should cool before downstream handling.
Cooling may be integrated into the soldering machine or provided by a separate conveyor.
Its role is to prepare the PCB for:
- Inspection
- Testing
- Manual handling
- Downstream assembly
Cooling capacity should match the soldering line throughput.
PCB Unloader
An automatic PCB unloader collects finished boards at the end of an automated line.
It can help:
- Reduce manual handling
- Maintain continuous production
- Organize PCBs in magazines
- Improve material flow
For low-volume lines, manual unloading may still be sufficient.
Post-Solder Visual Inspection Equipment
After soldering, PCBs should be checked for solder and component defects.
Typical inspection points include:
- Solder bridges
- Insufficient solder
- Poor wetting
- Incomplete hole fill
- Excessive solder
- Solder icicles
- Missing components
- Incorrect component position
Visual inspection can be supported with:
- Magnification systems
- Inspection lights
- Digital microscopes
- Inspection workstations
AOI Equipment
Automatic Optical Inspection can be used in some DIP/THT production environments.
Depending on the PCB and inspection capability, AOI may help identify:
- Missing components
- Position errors
- Orientation issues
- Selected solder defects
AOI does not replace all inspection or electrical testing.
Its suitability depends on component geometry and visibility.
X-ray is not required for every DIP production line.
It may be used where solder joints or structures are not easily inspected optically.
Whether X-ray is necessary depends on:
- PCB complexity
- Component structure
- Product quality requirements
- Inspection strategy
Factories should avoid adding high-cost inspection equipment unless the application justifies it.
ICT Equipment
In-Circuit Testing can be used to verify selected electrical characteristics and circuit conditions.
ICT may help identify issues such as:
- Open circuits
- Short circuits
- Incorrect components
- Selected component values
However, the exact test strategy depends on PCB design and test-point availability.
Functional Test Equipment
Functional testing confirms whether the assembled PCB performs according to its intended function.
Depending on the product, this may include:
- Power-on testing
- Communication testing
- I/O testing
- Relay operation
- Sensor simulation
- Programming
- Calibration
For industrial control and other complex products, functional testing can require significant time.
Therefore, testing capacity should be considered during DIP line planning.
Rework and Repair Stations
Even a well-controlled production line requires a defined rework process.
A rework station may include:
- Temperature-controlled soldering irons
- Desoldering tools
- Fume extraction
- Microscopes
- PCB fixtures
- Repair tools
The objective should be to minimize rework through stable upstream processes, but suitable repair capability remains necessary.
Fume Extraction and Ventilation
Fluxing, soldering, and manual repair processes may generate fumes.
Factories should provide suitable extraction and ventilation according to:
- Equipment configuration
- Flux chemistry
- Factory requirements
- Local safety regulations
The exhaust requirement should be considered before machine installation because it can influence factory layout and utility planning.
ESD Protection Equipment
Electronic components can be sensitive to electrostatic discharge.
A DIP assembly area may therefore require an appropriate ESD control system, including items such as:
- ESD workstations
- Grounding systems
- Wrist straps
- ESD flooring or mats
- Suitable storage systems
The exact ESD measures should follow the factory’s product and process requirements.
Typical Equipment List for a Complete DIP Assembly Line
A common semi-automatic line may include:
- PCB loader
- PCB conveyor
- Component preparation equipment
- DIP insertion conveyor/workstations
- Pre-solder inspection conveyor
- Wave soldering machine
- Cooling conveyor
- PCB unloader
- Post-solder inspection workstation
- Testing equipment
- Rework station
Additional equipment can be added according to production needs.
Recommended DIP Line for Low-Volume Production
For low-volume and high-mix factories, a simple configuration may be:
Manual PCB Loading → Component Preparation → Manual Insertion → Inspection → Wave/Selective/Manual Soldering → Inspection → Testing
Suitable For:
- Prototypes
- Small batches
- Frequent product changes
- EMS high-mix manufacturing
Advantages:
- Lower initial investment
- High flexibility
- Simple product changeover
The main limitation is greater dependence on labor.
Recommended DIP Line for Medium-Volume Production
A semi-automatic configuration can follow:
Automatic Loader → Insertion Conveyor → Manual/Semi-Automatic Insertion → Inspection → Automatic Fluxing → Preheating → Wave Soldering → Cooling → Unloader → Inspection → Testing
This can offer a practical balance between:
- Automation
- Investment
- Flexibility
- Production capacity
For many PCB assembly factories, this is one of the most versatile DIP configurations.
Recommended DIP Line for High-Volume Production
A higher-automation configuration may include:
Automatic PCB Loading → Automatic/Semi-Automatic THT Insertion → Automated Transfer → Inspection → Wave/Selective Soldering → Cooling → Automated Inspection → Testing → PCB Unloading
Additional systems may include:
- Automatic component feeding
- Barcode scanning
- Traceability
- Buffers
- MES integration
- Automated test handling
The investment should be justified by target capacity and expected utilization.
Wave Soldering or Selective Soldering: Which Equipment Should You Choose?
A major decision in DIP line planning is the soldering technology.
Wave Soldering Is Often Suitable When:
- There are many THT solder joints
- PCB design supports wave soldering
- Production volume is medium or high
- High throughput is important
Selective Soldering May Be Better When:
- Only specific THT joints require soldering
- There are many bottom-side SMT components
- Certain areas must avoid solder contact
- Products require localized soldering
Some factories use both processes because different products have different requirements.
How to Determine the Number of DIP Insertion Stations
Buying the correct soldering machine is not enough.
Insertion often becomes the bottleneck.
For example, if a PCB requires 80 seconds of manual component insertion but the wave soldering machine effectively processes one board every 30 seconds, the line cannot achieve a 30-second cycle time.
The manufacturer should instead consider:
- Splitting insertion between operators
- Adding workstations
- Improving component preparation
- Using semi-automatic equipment
- Automating suitable components
The objective is to balance the line.
Equipment Selection Should Start with the PCB and BOM
Before purchasing DIP line equipment, manufacturers should collect:
- PCB length and width
- Panel dimensions
- PCB thickness
- Maximum component height
- BOM
- THT component types
- Number of THT components
- Component packaging
- Target output
- Working hours and shifts
- Product mix
- Changeover frequency
- Required soldering method
- Inspection requirements
- Testing requirements
- Factory layout
- Existing equipment
- Automation level
- Budget
This information allows the equipment supplier to recommend a production line based on actual requirements rather than a generic equipment list.
DIP Equipment in a Complete SMT + THT Factory
Most modern PCB assembly factories do not operate DIP as an isolated process.
A complete PCBA flow may be:
Solder Paste Printing → SPI → SMT Placement → Reflow → AOI → THT/DIP Insertion → Wave/Selective Soldering → Inspection → Testing
Typical SMT-side equipment may include:
- Automatic solder paste printer
- SPI system
- SMT pick and place machines
- Reflow oven
- AOI system
- PCB loaders/unloaders
- Conveyors
The SMT and DIP sections should be balanced together.
A high-speed SMT line combined with insufficient DIP insertion or testing capacity can create large amounts of work-in-process.
New vs Pre-Owned Equipment for a DIP Line
Manufacturers can build a line using new equipment, suitable pre-owned equipment, or a combination.
New Equipment
Potential advantages include:
- New machine condition
- Current-generation functions
- Warranty options
- Longer equipment standardization horizon
Pre-Owned Equipment
Potential advantages may include:
- Lower initial investment
- Faster capacity expansion
- Access to established equipment platforms
Before purchasing pre-owned equipment, evaluate:
- Machine condition
- Configuration
- Maintenance history
- Spare parts availability
- Software
- Technical support
- Compatibility with production requirements
The purchasing decision should consider total cost of ownership rather than machine price alone.
DIP and PCBA Production Line Solutions from Fuliu Electronics
Established in 2014, Fuliu Electronics is dedicated to providing customers with high-quality PCBA intelligent manufacturing solutions and services.
With extensive experience in the SMT industry, we specialize in dependable equipment, professional technical support, and complete SMT and PCBA production line solutions.
Our product portfolio includes SMT pick and place machines from Fuji, Panasonic, ASM, Yamaha, JUKI, and Hanwha, together with ERSA reflow ovens from Germany, MagicRay SPI/AOI inspection systems, automatic solder paste printers, supporting PCBA equipment, pre-owned SMT equipment, SMT spare parts, machine leasing, and maintenance services.
For customers planning a DIP/THT line, Fuliu Electronics can help evaluate:
- PCB dimensions
- BOM
- THT component types
- Component packaging
- Production capacity
- Product mix
- Manual vs automatic insertion
- Wave vs selective soldering
- Inspection and testing requirements
- Factory layout
- Existing SMT/DIP equipment
- Automation requirements
- Budget and future expansion
Rather than purchasing individual machines independently, manufacturers can evaluate the complete SMT + DIP/THT production process to identify bottlenecks and build a more balanced PCBA line.
As part of our global growth strategy, Fuliu Electronics is actively expanding into international markets, with key focus areas including India, Vietnam, the Philippines, Indonesia, the Middle East, South Africa, and Europe.
Frequently Asked Questions
A basic line may include component preparation tools, insertion workstations, an inspection station, soldering equipment, post-solder inspection, testing, and rework equipment.
A more automated line may include PCB loaders, conveyors, automatic or semi-automatic insertion equipment, inspection stations, wave or selective soldering, cooling, unloading, and automated inspection or testing systems.
No.
Wave soldering is widely used for suitable PCBs with many through-hole joints, but selective soldering or manual soldering may be more suitable for some products.
There is no single most important machine.
Wave soldering is often a central process, but insertion, inspection, testing, and material preparation can also determine overall line capacity and quality.
Not always.
Manual insertion remains suitable for high-mix or lower-volume products. Automatic insertion is more appropriate when component types and production volume justify the investment.
An insertion conveyor provides PCB transport and workstation space for operators to insert THT components as boards move through the production area.