Manufacturing Considerations for Optimum

Throughput and Quality

Factory Automation Critical to US Manufacturers

• To compete domestically with offshore CM’s, to reduce man labor design’s

need to consider reducing use of manually installed (Thru-hole) components to

full extent possible.

•Isolate Thru-Hole from solder side SMT to allow access for selective soldering

and minimize masking requirements. (i.e. Connectors, Transformers, Relays….)

(consider pre-design meeting with manufacturing dept. / company)

• Maximize Computer Integrated Manufacturing - using CAM enables us to

optimize line efficiency, substantially improve our responsiveness and accuracy

•CIM can also be a baseline for a PLM Tools and – establish a forward

compatible package and part number library.

•Establish Consistency Now with component libraries, document formats and

define your Revision Control with PLM and factory automation in mind.

TJM Core Objectives

To deliver electronic hardware that is:

1) Built to print.

2) In conformance with specified standards.

3) Delivered on time.

TJM’s Value Added

• Communication • Response to RFQ’s

• Daily status updates

• Project interface (access to Insightly)

• We verify everything….

• DFM Report• Documents any design, documentation or data concerns

throughout the manufacturing cycle.

• Quality System AS9100• Exceeds commercial standards

• Delivery

• One week is currently standard

What has the most impact to meeting

these 3 main objectives?

1) Kit Condition (when customer supplies parts)

2) Lack of ASCII / CAD / (intelligent machine data)

3) Poor or incomplete documentation -no drawing is

provided, silkscreen does not have ref des, polarity and

orientation markings missing or ambiguous)

4) Layout / Design issues –Most are silkscreen,

panelization or fiducial related.

RFQ or Build Data / Document Checklist

Musts Nice to Have• ASCII CAD Data File

• Revision Controlled BOM

• Revision Controlled DWG

• XY file (if ASCII not avail.)

• Gerber Set

• Bare Board for Oven

Profiling (Baseline)

• Step File

• Schematic

• Board Fabrication Drawing

• Extra parts set for profiling

• Sample

Procurement /

Kit Staging

SMT

ASSEMBLY

Set UpCAM

FIRST

ARTICLE AOI Inspection

Touch up / TH Final Inspection Ship

ASCII CAD

File

CircuitCAM

Pick and

Place

Program

AOI

Inspection

Program

Color

Coded

Visual Aids

Build

Planning

ASCII CAD Design File

• CAD Data Includes: PWB dimensions, Pad geometries , part package geometries and part number information not provided in standard XY file.

• Improves our manufacturing efficiency, expediency, quality, and responsiveness.

• Minimizes the potential for human error (no manual entry)

• CAD Imports build your component library over time, reducing package and part number entry and programming from job to job.

BOM Import Sources and FormatsC

he

ckP

oin

t

Cir

cu

itC

AM

Text

(ASCII)Yes Yes

Fixed

Column or

Character

Excel Yes No N/A

ODBC

(Access)Yes No N/A

Format

Cost, Height

(mils)

Polarity,

Socketed

(Y/N,Yes/No

, T/F,

True/False)

Unlimited

Delimiters

Required

Fields

Preferred

Fields

Optional Text

Fields

Optional

Number

Fields

Optional

Boolean

Fields

Template

Definition, Join

Multiple Files to

Form 1 BOM,

Analysis

Reports, Use

Customer or

Internal Number

as Primary,

AML/AVL

Mgmt, Revision

Control

Additional

Functions in

CheckPoint

Custom

BOM Fields

Supported in…

Part

Number,

Reference

Designators

Description,

Quantity

(CheckPoint)

Part Marking,

Package,

Population

Type,

Customer P/N,

Mfr, Mfr P/N,

Vendor,

Vendor P/N,

Bin Location,

Stock Code,

Software Ver,

Part Rev, URL

Fiducials

• Most common problem we see is……there are none.

• Use of Fids are key to controlling #1 Defect –

(Tombstones)

• Have Global Fids in the design data (preferrably as the

origin 0,0.

• Use Panel Fids

• Once Global fids are used to set up program the panel fids (most often) can be used for production and reduce camera location time.

Fiducial Types

Yield Results using optimized fiducials

• Production Defect rate reduced to .012% (down

from 3%) on modules with 0402, 0201 and uBGA

packages.

• Touch up time reduced by 1/3 of the original

board build that had no fiducial locations.

Most Common Component Kit

Challenges• Exact Quantities ordered – No Attrition.

• Part ID - Customer provides alternates in the kit but does

not identify alternates on pick list and BOM. (we require to

get approval for substitutes to proceed)

• Chopped Tape Dilemma – Need to specify “continuous

tape” from Digikey/Mouser.

• Component Leads on fine pitch items damaged not

protected properly on multipin devices.

• Customer often holds kit until last item is received. Send

kits ahead for review and staging, drop ship final items.

WATCH OUTSome things we have come across recently..

Inconsistent Pad Geometry on BGA

Case sample: Samtec SeaRay

Connectors• Has an interesting interconnect technology (solder

charge)

• Recommends .006” thick stencil and (min of .005”)

• Recommends over sized apertures

Notes:If the solder charge does not collapse, due to incorrect stencil

parameters, part is difficult to remove, and is not re-useable. Note: we use

.004” thick stencils on 80% of our builds due to 0402 and 0201 passives. So

here is a situation where you have one part challenging the other for correct

tooling.

Please Don’t use…unless you have to

• White Solder Mask • Dark Ledger

White mask reflects light and reduces AOI image quality.

Machine operators can not see polarity markings or ledger through machine camera during set up

Panelization

• Stencil data in gerber set is for (1) unit. Array data

requirement must be communicated to, and provided by,

the board house.

• Why is that difficult to get that from Chinese board

vendors?

• Mousebites – Be careful where these are located, keep

away from traces, via, components in general.

• Prefer Scored Tabs – Careful about location.

• Be careful of long, thin scored boarders on boards .063 or

thicker. This inflicts mechanical stress on board while

trying to break border away

Keep Out Areas for Panel Tabs?

• Mousebites • Scored Tab

Fab Issues / Most common

• No Fab drawing and notes or Read-Me files for specs

• Clear stack up instructions

• Clarify material types, Copper Weights

• Trace and spacing should be no less than .005”

• Finished hole sizes .008” or above

•

Summary

• Providing ASCII CAD File is key to throughput and

accuracy

• Use Fids – Both Global and Panel

• Oven Profile is Critical – Spare Board and Parts provded?

• Consider letting CM (TJM) buy parts. It’s cleaner

• Mask vs PAD defined(see image)

• Watch for new component packages with special

requirements (Samtec SEARAY)