How Does MicroBlasting Clean Boards?
Micro‐precision sandblasting is a proven process for removing various types of contamination without damaging the leads or traces on the devices. In some cases, simply removing foreign material is sufficient to restore the board to a functional state.
Cleaning of a contaminated board is best performed by a manual blasting system with an enclosed workstation that confines the spent abrasive and provides a high visibility work area for the operator. The workstation should be equipped with static-dissipative devices to reduce the potential for static charge damage.
A Versatile Tool
MicroBlasting offers a cost-effective solution to many of the problems encountered when trying to salvage and recycle printed circuit boards. In addition to the selective cleaning example used in this overview, microblasting is used to remove conformal coatings from PC boards, trim epoxy from probe rings and for demarking electronics packages.
Contamination Removal from Set-Top PC Boards
When cable TV converter boxes or “Set‐Tops” fail, the high value of the boards and boxes warrants a significant effort to salvage these products. From coffee or soda to pet hair, contamination is often the source of a short or malfunction to the board. In order to recycle the returned board, it must be cleaned of all foreign substances and tested.
MicroBlasting is a fast, environmentally friendly, and cost‐effective solution to the problem of cleaning PC boards without causing damage to the board circuitry. It works by propelling air and abrasive out a small nozzle. The high velocity of the particles as they exit the nozzle greatly increases their abrasive action.
Board with contamination
Board, after removing contamination with MicroBlasting
What You Need to Get Started
Equipment: A manual system designed for static-sensitive applications. In this case: the AccuFlo® micro-precision blaster and the ProCenter Plus™ with ESD Control. (see below)
Media: 50-micron glass bead; removes residue without damaging components and or traces
Nozzle: 0.046” ID round nozzle; recommended for large, even coverage over the entire board
Nozzle Distance: 3-5” from the board
Blast Pressure: 60-80 psi
How to Clean with MicroBlasting
The operator should hold the nozzle a few inches from the board so that there is only light abrasion of the surface. Because of the small size of the nozzle opening, the operator can direct the abrasive stream with pinpoint accuracy and only blast sections of the board that are contaminated with foreign material.
The blasting process needs to be an even, controlled motion across the surface of the board. Care should be taken not to focus on any one section too long. If sprayed in one location long enough, the abrasive will start to damage the board. Once the board is clean, use an air gun to blown off any residual abrasive media.
Due to the variety of contamination types and levels of residue build-up, it may take anywhere from 15 to 45 seconds to process a board.
The ProCenter Plus™ with ESD Control
Any components that are sensitive to electrostatic should be processed in the ProCenter Plus™ with ESD Control. This unit delivers maximum protection against an ESD event.
What is the ProCenter Plus?
The ProCenter Plus is everything necessary to a MicroBlasting system except the blaster. It is a compact, chair-height workstation with an integrated dust collection system and an attached air dryer. It confines the blast area while a built‐in HEPA‐equipped dust collector extracts spent abrasive. It is easy to use and easy to maintain. The ProCenter Plus partners best with the AccuFlo® to form a complete manual MicroBlasting system.
The ProCenter Plus with ESD control has additional features that collaboratively neutralize surface charges and reduce electrostatic build-up.
Features that Neutralize ESD
The Ionizer Bar
Floods the entire work chamber with ionized air to neutralize static build-up. Built-in sensors monitor the effectiveness of the ion flow and indicator lights alert the operator to any changes in operation.
Works with the conductive nozzle to provide a conduit for static, sending it straight to the grounding jacks instead of onto a PCB.
Provide convenient connection points for a wrist-stat, the edge grounding bar, and the needle probe.
EDGE CONNECTOR GROUNDING BAR
Grounds all edge pins on boards that have edge connectors. This bar is made of conductive rubber material and connects to a grounding jack on the floor of the ProCenter Plus.
Pierces through the coating and grounds a target trace when the defect is known to be an open trace with no conductive path to ground.
Installed for coatings that are more easily visible under ultra-violet lighting.
|Available in:||115V / 60Hz, 4 amp
230V / 50Hz, 4 amp
|Dimensions:||30" wide x 46" high x 34" deep|
|Weight:||180 lbs (approx.)|
|Interior Space:||2.2 cubic feet, 24" wide x 10" high x 14" deep|
|Window:||Tempered glass opening (hinged) 23" x 11"|
|Lighting:||18W black fluorescent lights (2)
Optional: 40W cool fluorescent lamp
|Air Flow:||500 SCFM|
|Filter:||HEPA-99.97% efficiency on 0.3 micron-sized particles|
|Filter Area:||30 square feet|
|Inlet Air Pressure:||80 psi air supply of 10 SCFM in additional to normal blaster supply|