SMT Captive Screw

Fivetech Technology Inc.

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The SMT Solution for captive screw used on printed circuit board (PCB) enables a captive screw to be easily and accurately assembled to a PCB without deviation and skew.

Captive screw with a stop ring package

becomes a surface mounting device (SMD).

Employs the surface mounting technology

(SMT) for assembling a captive screw to PCB

just need one automatic process, differs

from press-fit style.

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Characteristic :

• SMT full automatic reflux welding process can increase production stability and production efficiency

• Welding for reinstallation can increase product reliability

• Reduce a damage risk of circuit caused during assembling

• Not need extra production line to punch captive screw( press-fit type need)

• Functional device(stop ring) which prevents thread damage caused by inflow of tin in SMT process

• Stop ring will achieve 100% pick and place yield rate

• Increase assembly efficiency & Economize manpower, time , money

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*Necessity to have stop ring during SMT process

All in one functional device(stop ring) will remove after SMT, and it provide:

A. accurate placement

B. solder stop

A. accurate placement:

a. Stop ring enables a SMT captive screw fix X ,Y axis(A,B,C) in horizontal

b. Stop ring enables a component to be easily and accurately assembled to a PCB without deviation and skew, no risk for PCB contamination during pick up & placement operation

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B. solder stop:

a. Stop ring will prevent thread damage caused by inflow of tin in SMT reflow process.

b. Stop ring keep 100% highly soldering reliability, prevent ferrule inner structure and screw thread damaged by inflow of tin that may result in float volume reduction or solder paste existed between PCB and outer ferrule flow into inner side that may occur unstable reliability or other concerns, therefore enhance failure rate and rework cost.

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c. Stop ring will achieve 100% pick and place yield rate.

Solve captive screw shifted problem during SMT pick up & placement operation caused by captivation structure or spring (The spring is forcing the screw in the open position, but it won’t always be straight). It may occur include but not limitation below issues:

1) It will be a problem to pick up slanted SMT captive screw, and may damage equipment due to unexpected condition during defected P&P operation

2) Ferrule may not paste well on the surface of PCB

3) SMT Captive screw tilted may loosen effective thread in P-2

4) Can not or not easily thread into nut due to slanted screw

5) The soldering interface(between solder pad & slanted component) may crack when tighten screw into nut

6) Using slanted SMT captive screw increase the risk of thread damage caused by inflow of tin in SMT reflow process

7) Slanted captive screws have ID concern

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Installation

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Stop Ring , removal after SMT process

Solder Paste

1.Preparation

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Reel or Tray

3.Heating to melt the layer

of solder, and cool down

2.Releasing the captive screw

from nozzle, falls with a flange

axially into the through hole.

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5.Down 4.Removing the stop ring.

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•Low profile design for hand operation

•SMT full automatic reflux welding process can increase

production stability and production efficiency

•Welding for reinstallation can increase product reliability

•Reduce a damage risk of circuit caused during assembling

•The specification could be customized

*Material of plastic knob can sustain the high

temperature in SMT process

*Production follows standard SMT process

*Color management is available as required by

customers

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