Rework of SMD Connectors

Due to their reduced space requirements, miniaturized SMD connectors are increasingly being used for small component assemblies, for example found in mobile devices

However, all SMD connectors aren't the same. There are significant differences in terms of layouts and shapes, sizes, used materials (affects allowed maximum temperature), surface conditions, design of contact areas and pins (symmetric/asymmetric, open/covered, number, shapes, pitch, etc.).

  • Insufficiently wetted SMD connector

What are the Challenges?

  • Replace missing, defect or misplaced SMD connectors
  • Integrate the entire rework cycle into the rework system
  • Increased requirements regarding placement accuracy
  • Precisely dosed dispensing of solder dots, even in places difficult to access
  • Avoid harm to neighbored components
  • Adapted handling to support a multitude of different connector layouts
  • In parts, very small and sensitive components (edge lengths < 3 mm, component height < 1 mm, pitch = 0,25) require specific solutions for pick-up from tray, tape, waffle pack, etc. via tool vacuum

The Finetech Solution

Typical Rework Cycle

The full rework cycle for SMD connectors includes the following typical working steps:

  • De-solder SMD connector
  • Residual solder removal, cleaning (if necessary)
  • Solder paste application (paste printing head, dispensing)
  • Solder SMD connector, cleaning (if necessary)

Process step 1: De-soldering the SMD Connector

Flash is required!
  • Design of soldering head adapted to the layout of the SMD connector (clamping, vacuum support, etc.)
  • Uniform heating of all contact pads (open/covered)

Process step 2: Residual Solder Removal and Cleaning

  • Flash is required!

  • Pads with residual solder
  • Pads cleaned from residual solder
  • Solder removal heads in different sizes and with adapted vacuum support (interior diameter of 0.3 mm and smaller)
  • Protection of neighbored components by use of suitable solder removal heads with screening tube
  • Contactless process

Process step 3: Solder Paste Application

  • Linear solder paste spreading
  • Due to restricted space a use of printing stencils / paste printing heads is hardly possible
  • The alternative is to apply solder paste using a dispenser
  • Processing of various solder pastes (down to Super-Fine-Pitch of 5…15 µm) is supported by adapting syringe and needle sizes
  • Benefits of a dispensing unit:
  1. High-precision (placement, dosing)
  2. Reproducibility (placement, dosing, dispensed patterns)
  3. Adaptation (e.g. switch of syringes, various needles)

Process step 4: Soldering of the SMD Connector

  • Flash is required!

  • Alignment with overlay images
  • Soldered connector, top view
  • Soldered conector, side view

Alignment with overlay image

  • Adapted soldering heads capable of fixating and placing the component (ideally, soldering and de-soldering can be done with the same soldering head)
  • High-precision placement
  • Detection of misplaced components, placement errors, etc.

Soldering process

  • Easy to highly complex soldering processes are supported
  • Adaptation of all process parameters with regard to sensitive components (temperature, flow, time)
  • Active flow control to avoid disturbance of adjacent components
  • Defined cooling process to prevent from tensions / warpage

Controlled Mixed Soldering System

  • Flash is required!

  • Controlled Mixed Soldering System

Finetech’s unique thermal management concept uses “cold” air or gas (typically nitrogen) introduced into the hot-gas stream in a mixing chamber. The chamber location is just before the air passes through the nozzle onto the component. This gas mixture results in a highly responsive system - reducing over and under-shoot to barely perceptible levels. Tracking of the pre-set temperature is optimized and when combined with mass-flow-control of gas volumes (up to 70L/min), produces an effective heat delivery system. Heater lifetime is also increased and system-to-system reproducibility is greatly enhanced (±2ºC).

Integrated Process Management (IPM)

  • Integrated Process Management (IPM)
  • Principle of process gas integration
  • Operating software for rework

The Integrated Process Management (IPM) is the center piece of a FINEPLACER® system1 - the place where it all comes together. IPM is more than just thermal management. It synchronizes the control of all process modules and their related parameters:

  • Controlled and precisely balanced interaction of top and bottom (pre-)heating and cooling
  • Control of temperature, time, force, power, energy, flow
  • Process-integrated camera and light control
  • Controlled process gas integration for reduced solder contamination, minimized surface tension effects and smooth spherical solder residues

 IPM is very complex, yet easy to access. Via the GUI of the operating software, the user has perfect control of all required adjustments. Just drag 'n drop to define temperature ramps or activate process modules. All settings are represented in only one profile, making for a very intuitive work flow.
 
The operating software provides an ever-growing library of profiles for all kinds of processes. It also offers comprehensive data logging functions essential for statistical process control.

In combination with the system-to-system process transfer capability this is as easy as process development can get.

1 FINEPLACER® core offers co-ordinated top and bottom heating but does not support IPM

FINEPLACER® Rework Systems

  • FINEPLACER® coreplus
    Rework of medium-sized boards
  • FINEPLACER® pico rs
    High density rework station
  • FINEPLACER® micro rs
    Hot air SMD rework station

Amongst other factors, the recommended system mainly depends on size and pitch of your component and the required process flexiblity.

Browse our product range or get in contact with your sales contact to figure out the best equipment solution for your needs.

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