SMT Process flow chart

Surface-mount technology (SMT) is a method for producing electronic circuits in which the components are mounted or placed directly onto the surface of printed circuit boards (PCBs). An electronic device so made is called a surface-mount device (SMD).

The flow chart for SMT is as follow:

 

Attenuation of Coaxial Cable

The power loss caused by a coax cable is referred to as attenuation. It is defined in terms of decibels per unit length, and at a given frequency. Obviously the longer the coax cable, the greater the loss, but it is also found that the loss is frequency dependent, broadly rising with frequency, although the actual level of loss is not linearly dependent upon the frequency.

Attenuation of coax-cables is described as the attenuation of the individual parts. Inner conductor, dielectric and outer conductor attenuation form the overall attenuation of the cable according equation [1].

α_tot = α _i+ α _foam+ α_o                                                                               [1]

The individual components are described with equation [2], [3]and [4].

Attenuation of inner conductor

α _{i             =}          36.1*k_i *√f / Z_c*d_e                                             [2]

Attenuation of outer conductor

α _{o          =}          36.1*k_o *√f / Z_c*D_e                                                          [3]

Attenuation of the dielectric layer

α_foam =     9.096 *√ ε_r* tan δ *f                                               [4]

α _i        -           attenuation inner conductor [dB/100m]

α _o        -           attenuation outer conductor [dB/100m]

α_foam     -           attenuation dielectric layer [dB/100m]

Z_c         -           characteristic impedance [ohm]

f           -           frequency [MHz]

ε_r          -           dielectric constant

k_i         -          shape factor inner conductor

k_o         -           shape factor outer conductor

d_e         -          electrical equivalent inner diameter

D_e        -          electrical equivalent outer diameter

The electrical equivalent diameter considers the skin effect, which occurs on high frequency signals where the current tends to flow only in a very thin skin layer. The depth of penetration is given by following formula.

‘δ       =      15.9 / √(σ*f )

δ          -          conducting layer         [mm]

σ          -          conductivity                [m/Ω mm²]

f           -           frequency                    [kHz]

With above relation

de = di _CU  – 2* δ

De = Do _CUinner + 2* δ

8D format example

                                               YOUR COMPANY NAME

                                        NON CONFORMANCE REPPORT

NCR NO.	REF. REPORT NO.				DATE:
PROCESS STAGE		DEPARTMENT/SUPPLIER
NCR RESPONSIBILITY:			REF. ITEM:
NON CONFORMITY OBSERVED
IMMEDIATE ACTION				DATE/DONE BY:
ROOT CAUSE ANALYSIS: ROOT CAUSES: DECISION:				DATE/DONE BY:
PLANNED ACTION				DATE/DONE BY:
IMPLEMENTED CORRECTIVE ACTION				DATE/DONE BY:
ACTION TO PREVENT OCCURRENCE				DATE/DONE BY:
VERIFICATION CLOSURE				DATE/DONE BY:

ADDITIONAL DOCUMENTS ATTACHED:

For information on 8D methodology please click 8D Methodology

Knowledge Guru

REGRESSION ANALYSIS

In scientific research/industrial problem solving often a situation is encountered  where in  a number of variables are involved with possible interactions or relationship among themselves.

Regression analysis is a statistical technique for investigating and modeling relationship among these variables in such situations. As an example, consider the Current and Plating Thickness in electroplating. One may be interested to find out whether they are related and if so, what is the form of relationship. The relationship may be expressed in the form of an equation or model connecting one of the variables, known as the response or the dependant variable (denoted as Y) with one or more other variables known as explanatory or predictor or independent variables (denoted as X or X1, X2,X3 etc.).

The variables can be either quantitative or qualitative.  Examples of quantitative variables are measurable variables like hardness, tensile strength, diameter, width,  etc. Examples of qualitative variables are good/bad, defective/non-defective, religion, sex, region etc  

Applications of regression analysis are numerous and occurs almost every field, including engineering, quality control, physical and life sciences, economics, management, social sciences etc.

DIFFERENCE BETWEEN ISO 9001:2008 & ISO 9001:2015 STANDARDS

Followings are the  difference between ISO 9001:2008 & ISO 9001:2015 standards:

ISO 9001:2008	ISO 9001:2015
0. Introduction	0. Introduction
1. Scope	1. Scope
2. Normative References	2. Normative References
3. Terms and Definitions	3. Terms and Definitions
4. Quality Management System	4. Context of the Organization
5. Management Responsibility	5. Leadership
6. Resource Management	6. Planning
7. Product Realization	7. Support
8. Measurement, Analysis and Improvement	8. Operations
	9. Performance Evaluations
	10.Improvement

CLAUSES OF NEW ISO 9001:2015 STANDARD

Followings are the new clauses of new ISO 9001:2015 standard:

0. Introduction

1. Scope

2. Normative References

3. Terms and Definitions

4. Context of the Organization

5. Leadership

6. Planning

7. Support

8. Operations

9. Performance Evaluations

10.Improvement

INSERTION LOSS

Transmission feed line system performance plays an important

role in wireless network coverage. Insertion loss measurement

is one of the critical measurements used to analyze transmission

feed line installation and performance quality. 

In wireless communication systems, the transmit and receive

antennas are connected to the radio through coaxial cable

and/or waveguide transmission lines .

Insertion loss measures the energy absorbed by the transmission

line in the direction of the signal path in dB/meter or dB/feet.

Transmission line losses are dependent on cable type, operating

frequency and the length of the cable run. Insertion loss of a

cable varies with frequency; the higher the frequency, the

greater the loss.

In other words, insertion loss is the loss of signal power resulting from the insertion of a device in a transmission line or optical fiber and is usually expressed in decibels (dB).

If the power transmitted to the load before insertion is P_T and the power received by the load after insertion is P_R, then the insertion loss in dB is given by,