Drilling speed

In practice the drill speed and feed rate can be increased for maximum production provided that there is no melting, burning, discoloration or poor surface finish. For deep drilling, frequent withdrawal of the drill may be necessary for chip ejection. 

T. Lizotte and O. Ohar, Laser drilling speeds BGA packaging, Solid State TkchnoL, 39 (1996) 120-125. 

Mesh size in drilling tools has a dramatic impact in drilling speeds, which can be increased from 1000 to 6000 rpm along with a force reduction on the diamond core bit by a factor of nearly 6.8. ... 

Figure 5.6a shows experimentally measured drilling speeds in glass with a 0.4 mm stainless steel tool-cathode. The electrolyte used was 30 wt% NaOH. By comparing the measured drilling speeds with that computed using Equation (5.20), it is possible to determine the dependence of the normalised heat power... 

Typical examples for glass drilling as a function of various machining voltages are shown in Fig. 6.2. Drilling was done with a 0.4 mm cylindrical stainless steel cathode in 30 wt% NaOH [131]. After a first phase, where the drilling speed is fast, a progressive slow down of the material removal rate is observed... 

The discharge regime in glass gravity-feed drilling is characterised by a high drilling speed of typically 100 J.m/s [131]. It takes place in the first 100-200 lm. 

R. Wiithrich, B. Despont, P. Maillard, H. Bleuler Improving drilling speed in Spark Assisted Chemical Engraving (SACE) by tool vibration. Journal of Micromechanics and Microengineering 16 (2006), pp. N28-N31. 

Early wells were sunk by ramming. This was replaced by rotary drilling, where the bit turns at 50 to 300 revolutions a minute. Different bits are used for soft or hard rocks or coring. They tend to crumble the rock. Drilling speed can vary from 8 inches an hour in hard rocks to 100 feet per hour in soft ground. 

In order to solve this problem, I am glad to introduce the reverse circulation DTH hammer drilling technology (Fig. 2), which had outstanding advantages in complex formation drilling. It had fast drilling speed, low air requirement, and not be affected by the formation condition etc. 

Drilling speed should be really fast to make sure that the isolated area could be drilled through timely. 

Remember, the larger the drill bit, the slower the drill speed. 

A diameter of 1 mm, 1.7 mm and 2 mm steel partieles are used in the experiment. The drilling fluid density is 1.32 g/em, and the drill speed is 90r/min. Under different partiele sizes, fluid displaeement and the average annulus veloeity, the experiments are eondueted. 

When the dielectric is resin without copper foil, a CO2 laser is the best since a CO2 laser can offer much faster drilling speed (a single-head CO2 laser can drill as many as 25,000 holes per minute, including overhead such as loading a panel onto the drilling table and... 

When the surface is resin only, a single-headed CO2 laser machine can drill holes at the rate of 20,000 to 25,000 per minute depending on hole density and distribution. The drilling speed continues to increase. The denser the hole, the faster the drilling speed because time lost by table motion is minimized. A dnal-head CO2 machine can boost drilling productivity by about 70 percent compared to a single-head machine. 

Alternatively, ultrathin copper RCC may be used. Carrier foil, usually copper foil of IQ-jim thickness (2 oz.), is coated with a very thin layer (10 to 20 m) of current conductive release film, and a thin foil of 3 to 5 pm is plated. After such RCC is laminated to the core, the carrier film is peeled off and the surface condition is the same as etched-down copper. Drilling speed in this direct CO2 laser drilling method is degraded by 30 to 40 percent compared to that of straight resin drilling, but the registration to the capture pad is ensured. 

Resin smear can cause weak connections between plated-through-holes and innerlayer copper that fail under environmental stress. There is always some resin smear, which is removed by the desmear (etchback) process. If the desmear process is not effective, or if the resin smear is excessive, poor interconnection to the innerlayers can result. Possible causes of excessive smear are a dull drill or the wrong feed rate or drill speed, all of which can cause increased drill heating, resulting in more smear. 

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