Decision Matrix Flow Chart

Flowchart Introduction

The flowchart is a way to aid in the decision of which process to use by asking simple questions about the board design and the difficulty of fabricating the board.

The flowchart is provided as a means of suggestion for which is likely to be the best process for fabrication. The final decision requires the user to make an informed decision based upon the project specifics that are beyond the scope of this flowchart, decision matrix, and document.

Flowchart

Figure 1 below shows the flowchart. The first six questions (following the perimeter of the flowchart in a counter-clockwise manner) rule out any boards requiring fabrication techniques that are not able to be performed as DIY.

“THP?” If the board requires through hole plating, then it must be out sourced to a commercial fabricator.

“Number of Layers?” Because of the difficulty in producing a multi-layered board (i.e., more than two layers) any board requiring more than two layers must be out sourced to a commercial fabricator

“Metal Type” Anything beyond copper-clad boards or any kind of plating requires out sourcing to a commercial fabricator.

“Gold Finger?” A board requiring gold requires out sourcing to a commercial fabricator.

“Solder mask?” & “Silk screen?” Both of these require out sourcing because of the sophisticated equipment.

For the seventh question “Schematic hand drawable,” if the schematic can be hand drawn then both the sharpie and rub-on methods are likely to be the best choice.

For the eighth question “Difficulty(),” see the Decision Matrix section after the flow chart.

For the seventh question “Schematic hand drawable,” if the schematic can be hand drawn then both the sharpie and rub-on methods are likely to be the best choice.

For the eighth question “Difficulty(),” see the Decision Matrix section after the flow chart.

Figure 1. shows flow chart

Decision Matrix

In order to evaluate the eighth question “Difficulty()” in the flowchart in Figure 1, the following twelve questions need to be answered. Each answer is awarded a point value, which are summed up to produce a final score. Since there are negative point values, the decision process starts with fifteen points to produce a final score between 0 and 76.

Start with 15 points:
Q1: Ever done wet etch? Yes (-5) No (+5)
Q2: Single sided? Yes (0) No (+8)
Q3: Board dimension? Small (+1) Medium (+2) Large (+5)
Q4: Trace widths? <= 0.05" (+5) Otherwise (0)
Q5: Trace pitches? <= 0.05" (+5) Otherwise (0)
Q6: Surface mount parts? Yes (+8) No (0)
Q7: Ever done PCB soldering? Yes (-5) No (0)
Q8: Ever done SMT soldering? Yes (-5) No (0)
Q9: Board quantity? 1 (0) 2-4 (+3) 5+ (+6)
Q10: Number of holes? 0-24 (0) 25-49 (+3) 50+ (+6)
Q11: Number of parts? 0-9 (0) 10-24 (+3) 25+ (+6)
Q12: Component pitch? <= 0.05" (+7) Otherwise (0)

After calculating the final score, the difficulty level used in the flow chart will be low, medium or high. These three levels are determined using the following ranges

Low difficulty: 0 to 24
Medium difficulty: 25 to 39
High difficulty: 40 to 76

After using the difficulty level in conjunction with the flow chart, use the step-by-step instructions given under DIY tutorials click here to go there.