The Critical Purpose Of Solder Paste Printing In New Product Intro

Surface mount assembly (SMT) has a crucial role to try out from the New Product Introduction (NPI) process for electronics manufacturing.

Our prime amount of automation within the SMT methodology provides a number of advantages, from automatic correction of errors, to simpler and faster assembly, better mechanical performance, increased production rates and reduced labour costs.

The SMT assembly process with an electronics manufacturing services (EMS) provider can be broken down into four key stages:

Solder Paste Printing
Pick and put
Oven Profiling
Automated Optical Inspection (AOI)
Based on the complexity of the design, maybe own outsourcing strategy, your products or services could go through each of these processes consequently, or else you could find which you omit a measure or two.

We want to highlight the particular attributes, and also the vital importance, of the solder paste printing process for your NPI.

Trying to your specifications
The first task for your EMS provider is to analyse the printed circuit board (PCB) data that’s specific for your order, to make sure that they pick the required stencil thickness as well as the the most appropriate material.

Solder paste printing is the most common method of applying solder paste into a PCB. Accurate solder paste application is hugely essential in avoiding assembly defects which can use a knock on effect further down the production process. So it’s vital that this key stage is correctly managed and controlled because of your EMS partner.

Solder paste it’s essentially powdered solder that has been suspended inside a thick medium called flux. The flux behaves as a sort of temporary adhesive, holding the constituents in place before soldering process begins. Solder paste is used to the PCB by using a stencil (generally stainless-steel, but occasionally nickel,) then as soon as the solder is melted it forms an electrical/mechanical connection.

The thickness in the stencil is exactly what determines the total number of solder applied. For many projects it may also be important to have several thicknesses in various areas inside the one stencil (known as a multi-level stencil).

Another key factor to think about within the solder printing process is paste release. The correct sort of solder paste must be selected based on how big the apertures (or holes) within the stencil. If your apertures have become small, as an example, then the solder paste could be more prone to sticking with the stencil rather than adhering correctly to the PCB.

Governing the rate of paste release however can be easily managed, either start by making changes towards the design of the aperture or by reduction of the thickness from the stencil.

The kind of solder paste that is used could also affect a final top printing quality, therefore it is crucial that you find the appropriate combination of solder sphere size and alloy for that project, and also to make sure it is mixed to the correct consistency before use.

Ensuring quality
When the stencil has become designed and your EMS partner is able to make the first PCB, they’re going to next want to think about machine settings.

Quite simply, the flatter you can maintain the PCB over the printing process, better the final results will likely be. So by fully supporting the PCB through the printing stage,either by way of automated tooling pins or with a dedicated support plate, your EMS provider can remove the potential for any defects including poor paste deposit or smudging.

You’ll want to consider the speed and pressure with the squeegees in the printing process. One solution is to have one speed to the solder paste but to possess varying degrees of pressure, using the unique specifications in the PCB along with the whole squeegee.

Washing the stencils, both before and throughout production, is likewise crucial in ensuring qc. Many automatic printing machines possess a system that can be set to scrub the stencil after having a fixed number of prints which will help to prevent smudging, and prevents any blockages of the apertures.

Finally too, the printers should have a built-in inspection system (like Hawk-Eye optical inspection) which can be preset to observe a good paste across the whole PCB after printing.

The solder paste printing process is a precise and detailed the one that have a significant part to learn within the ultimate success of one’s awesome. And, simply because this short article highlights, a lot of detailed tasks are planning to occur behind the curtain before your EMS partner solders the first electronic element of a board.

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