1. Generally,SMT workshop sets temperature at 25±3℃

2. Materials and Tools for Preparation of Tin Ointment, Steel Plate, Scraper, Scrubbing Paper,Dustless Paper, Cleaning Agent, Mixer;

3. Generally used tin paste alloy composition is Sn/Pb alloy, and the alloy proportion is 63/37;
4. The main components of tin paste are divided into two parts: tin powder and flux。
5.  The main function of flux in welding is to remove oxide, destroy the surface tension of tin melt and prevent reoxidation。

6. A ratio of tin powder particles to Flux( flux) in tin paste is about 1:1 in volume and 9:1in weight;

7.  The principle of taking tin paste is first in first out;
8. When the tin paste is used in Kaifeng, it must go through two important processes to warmand stir;

9.  The common methods of making steel plate are: etching, laser, electric casting;
10.  The full name of the SMT is Surface mount (or mounting) technology;
11.  ESD name is Electro-static discharge;
12.  When making SMT equipment program, the program consists of five parts: PCB data;Mark

data;Feeder data;Nozzle data;Part data;

13.The melting point of lead-free solder Sn/Ag/Cu 96.5/3.0/0.5 is 217 C. 
14.  Control relative to temperature and humidity of drying box <10%;
15.  The commonly used passive components (Passive Devices) are: resistance, capacitance, point sense (or diode); active components (Active Devices) are: electro-crystal, IC, etc.

16. Common SMT steel plates are made of stainless steel;
17. The thickness of commonly used SMT plates is 0.15 mm (or 0.12 mm);
18. The types of electrostatic charge are friction, separation, induction, electrostatic conduction, etc. The influence of electrostatic charge on the electronic industry ESD failure, electrostatic pollution; electrostatic elimination of the three principles for electrostatic neutralization, grounding, shielding。

19.Size length x width 0603=0.06 inch*0.03inch﹐ metric length x width 3216=3.2;
20. discharge resistance ERB-05604-J81 yard 8"4" is expressed as 4 loops with a resistance value of 56 ohms. ECA-0105Y-M31 capacitance C=106 PFC=1 NF C=1

21. ECN  full name is: engineering change notice; SWR Chinese full name is: special needs work order, must be countersigned by the relevant departments, document center distribution to be effective;
24. Quality policy is: overall quality control, implementation of the system, to provide customer demand quality; all staff participation, timely processing, in order to achieve the goal of zero;
25.  Quality three non-policy: do not accept bad goods, do not make bad goods, do not outflow bad goods;
26. The reasons for fish bone examination in the seven major manipulations of QC M1H are: human, machine, material, method, environment;
27.  Tin paste is composed of: metal powder, soluble, flux, anti vertical flux, active agent; by weight, the metal powder accounts for 85-92%, by body integral metal powder accounts for 50% metal powder is tin and lead, the proportion is 63/37, the melting point is 183℃;

28.The tin paste must be removed from the refrigerator to return temperature, the purpose is: refrigerated tin paste temperature to return to normal temperature for printing. The tin beads are easily produced after PCBA Reflow if the temperature is not returned.

29. The machine's file supply modes are: ready mode, priority mode, exchange mode and speed mode.;
30.  SMT PCB positioning methods are: vacuum positioning, mechanical hole positioning, bilateral clip positioning and plate edge positioning;
31. Screen (symbol) is 272 resistance, resistance value is 2700Ω, resistance value is 4.8 MΩ of the symbol (screen) is 485; 
32.  Screen printing on the BGA body contains information such as manufacturer, manufacturer's material number, specification and Datecode/.;
33.  The pitch of 208 pinQFP is 0.5 mm. ;
34.  Among QC seven techniques, the fishbone diagram emphasizes the search for causality;
37.  CPK means: Process capability under actual conditions;
38.  The flux starts to volatilize in a constant temperature zone for chemical cleaning;
39.  Ideal cooling zone curve and reflux zone curve mirror relationship;
40.  RSS curve → constant temperature → reflux and cooling curve;
42.  PCB warpage specification does not exceed 0.7% of its diagonal;
43.  STENCIL laser cutting is a way to rework;
44.  The BGA ball diameter on computer motherboard is 0.76 mm.;
45.  ABS system absolute coordinates;
46.  The capacitance ECA-0105Y-K31 tolerance of ceramic chip is ±10%;
48. SMT parts package with a reel of 13"7" diameter;
49. To prevent tin ball bad phenomenon, the opening of SMT steel plate is usually 4 um smaller than that of PCB PAD.;
50.  Non-attachment between solder paste and wave solder is indicated when dihedral angle >90 degrees according to PCBA Inspection Code;