57. Advanced Brazer Training

Braze training can make a tremendous difference in the quality of the operation

Deliverables on Previous Projects

¨       Eliminate tungsten carbide breakage entirely

¨       Reduce tungsten carbide braze failure to six sigma (3 parts per million)

¨       Eliminate rework

¨       Improve bond strength by 40% eliminating braze failure

¨       Double tool run time

¨       Increase coolant life from 2 weeks to six months

¨       Eliminate safety and health risks due to Cadmium

¨       Reduce safety and health risks due to Cobalt

¨       Reduce costs of labor and materials by 60%

¨       Smoother finishes

¨       More precise cutting

Brazing Program Impacts

Cost reduction

Cross-functional team building

Greater tool reliability

Safety and health

Environmental

Brazing Program Requirements

·         Cross functional teams: Interdisciplinary, Interfunctional, and Concurrent engineering

·         Hard Data - Numbers

·         Prints and specifications for tool bodies

·         Tool performance data

·         Comparison of good to bad tools

·         Tool running instructions

·         Employee commitment to change

·         Employee ability to change

·         Management buy-in

·         Analyze current data

The topics covered are as follows:

1.       Safety and health

2.       Physics of brazed tools

3.       Braze alloy chemistry

4.       Differences in braze alloys

5.       Parts cleanliness in brazing

6.       Braze joint clearance - Designing braze joints for tensile strength

7.       Designing braze joints for impact protection

8.       Temperature control

9.       Using SPC in brazing

Determining what to measure

Establishing upper and lower SPC standards

Establishing production floor testing

Incorporating SPC in the production process

10.   Identifying braze failure

Compiling braze failure data

Analyzing braze failure from data

11.   Tool tipping materials - Tungsten carbide grades, uses and selection

12.   Grinding operations as related to brazed tools

13. Identifying improved tool performance

            Gross breakage

            Microfracturing

            Measuring run life

 Quality procedures

Establishing inspection points

Establishing inspection parameters

Documentation

Standardizing procedures

Establishing written procedures

Special emphasis on:

Temperature

Most common causes of braze failure in order.

Wrong Braze alloy is the major reason for breakage and loss

Improper fluxing

Switching from Black Flux to White Flux can cause tip loss.

Watery Flux

Dried or old flux

Improper braze joint thickness

Too thin a braze joint

Uneven solder – poor tip placement

Uneven solder – poor wiping motion

Tip placement

Improper cleaning

Improper brazing temperature

Underheating the solder

Overheating the solder

Colors in the solder – burnt solder can have a green or pink/rose color to it

Gas entrapment

Wrong flux

Underheating

Overheating

Surface condition of the tip

Overheated tungsten carbide

A combination of things

SPC Considerations in Braze Failure

·         Engineering sets a needed specification for brazing of 100

·         We set the SPC limits from 110 to 130

·         The system is engineered to deliver 150 when everything runs right but we only need 100.

·         For impact

·         Fluxing

·         Heating

·         Part movement during brazing

Example

·         If everything works right we get a value of 150 and we need 100

·         If one part is at 90% we get 90% of 150 which is 135.  We need 100 and we are good

·         If 2 parts are at 90% then we get 90% of 90% which is 81%.  81% or 150 is 121.50 and we are good.

·         3 parts at 90% is 72.9% of 150 which is 109.35

·         4 parts is 65.6% of 150 = 98.4 and we have tool failure

Examples

I developed a program for brazers in an aerospace company.  They considered their company high tech and they considered sawmills as definitely low tech.  Fortunately Timber Processing magazine had an excellent article on Sun Studs which is really high tech in brazing tools.  It did a nice job of opening some eyes in aerospace.

Brazers in saw mills

1.       Inspect incoming tool bodies (saws, shapers, routers, band saw, planer knives, etc.,)

2.       Accept or reject the bodies

3.       Repair bodies

Tension

Flatness

Cracks

Wear

4.       Resurface body before brazing

5.       Specify tool tip material

6.       Clean tool tip material

7.       Flux

8.       Braze

9.       Inspect

10.   Track tool performance

11.   Track each tool individually

12.   Specify tool design and re-design

13.   Maintain equipment

Sun Studs article in Timber Processing magazine

Exact placement of induction heating

Computer controlled brazer

Digital feedback screen

Video inspection system

1.       All tools are inspected against original specifications

All tools are brought back to original specs before re-use

Within one half thousandth 0.0005”

Fit and flatness – Darryl’s question about gaps

            Ribbon is flat

Tungsten carbide is flat

If body is flat then flux and dirt are only possible source of problems

2.       Material selection

Different materials used depending on task to be done

3.       Heating

Calculated, measured, preset exact heating

Tungsten carbide position +/- 0.001” / 0.002”

Black Flux

Video inspection system

Calibration marks

No Cadmium

4.       Tungsten carbide grinding

Precision automatic machines

            CNC

            “Screw” type

            Cam controlled

All hydraulic

All flutes ground exactly equally

5.       Records

Records kept of each tool by serial number

Every tool has a computerized history

6.       Equipment maintenance

Serviced and checked daily

Also weekly and monthly

Annual total rebuild

7.       Performance

In the cut saw monitoring systems

Amperage draws to determine edge condition

Specified run-times for tools

2.5 hours for band saws

5 hours for round saws

Recommendations

1.       Start keeping records

1. Measure what you think might be important to see if it really is.

2. Add or delete recording keeping as it seems important

2.       Get original specifications where available

3.       Test to see if those specifications are still valid

4.       Do not use out of spec parts and materials

You can make good tools out of bad parts sometimes but the odds are against you.

5.       Same with equipment

Find out how the equipment is supposed to perform.

Figure out or find out how to test to see if it is performing properly.

6.       Set upper and lower limits for acceptable performance everywhere:

Roughly:

Upper limits that are too high mean too much expense

Lower limits too low mean tool failure

7.       Figure out easy, simple plant floor measurements for performance

8.       Some tools are bad – eliminate those – you may not know why but the record will just show that some break more than others do

9.       Compare good tools to bad tools every way you can

Test to see which differences are important

10.   Work with other people in other departments