As a specialized manufacturer of knives, Guanzhong Tools Co., Ltd. is known for producing a wide range of specifications with high output. The turning of the tool taper shank is typically a slender shaft, which presents significant challenges during processing. Traditionally, the process relied on templates, where the lathe's small slide was manually fed. When adjusting the taper, the template’s taper was loosened, and after adjustment, the press plate was locked to begin processing. However, this method had several drawbacks: 1) unstable quality, 2) poor straightness of the cone's surface, 3) occasional chipping, 4) rapid wear of the template plate, 5) issues with the saddle movement when the pressure plate was too tight or too loose, 6) excessive diameter variation when there was a large machining allowance, and 7) black skin formation after heat treatment, leading to waste. These issues necessitated a technical upgrade in the turning process.
To address these challenges, we decided to retrofit an economical CNC lathe. We selected an older C616 lathe and modified it by removing the gear box, the wheel box, and the three bars, while scraping the guide rail surfaces. We installed the BKC-5E CNC system from Xi'an Micro-Electrical Research Institute, along with two ball screws for longitudinal and transverse movement, mounted directly onto the bed. The ball screws were connected to stepping motors via sleeve couplings with a 1:50 taper pin. The original square tool holder was retained, and the X-axis was used for horizontal movement while the Y-axis handled vertical movement, enabling coordinate linkage.
As an example, we took the f32mm taper shank end mill for demonstration. The blank drawing, process sketch, and clamping method are illustrated in Figures 1, 2, and 3 respectively. The turning process was divided into five steps: tailstock, roughing, fine turning, necking, and slotting. The workpiece was mounted directly on the spindle, supported by a live center at the tailstock, and clamped using a clip. Loading and unloading were quick, taking only about 30 seconds. Processing all five steps in one setup took just 1–2 minutes, significantly improving efficiency.
The machining program was written as follows (excluding roughing):
N1 G22 L99 LF
N2 G92 X33 Z152 LF
N3 G00 X25.1 LF
N4 G01 Z143.0 LF
N5 G00 X26.4 LF
N6 G01 X28.90 Z63 F26 LF
N7 G00 X26.4 LF
N8 G01 Z43.8 F24 LF
N9 G00 X30 LF
N10 G00 Z110 LF
N11 G01 X26.3 F26 LF
N12 G01 Z100.8 F26 LF
N13 G27 LF
N14 G29 LF
N15 G80 LF
N16 M20 LF
For tool setting, we developed a practical and efficient method. A 45° turning tool was ground and mounted on the square tool holder. During installation, the right end of the workpiece was measured with a caliper, and the tool tip was positioned 3–5 mm away from the outer edge. After entering the program, test cuts were made, and measurements were taken gradually until the required dimensions were achieved. When changing tools, the same process was repeated, requiring secondary tool setting. This method is simple, fast, and cost-effective, especially for companies without indexable cutting tools.
After successful testing in our milling cutter workshop, the new method proved highly effective. It ensured stable and reliable quality, improved straightness, reduced surface roughness, increased productivity, and lowered tooling costs. It also eliminated the need for expensive indexable carbide tools, allowing the use of standard welding-type tools. Additionally, it simplified the grinding process, making it manageable for regular machinists.
By implementing this approach, we have transformed eight economical CNC lathes (C616 and C620 models), which are now used to process tapers on various tools such as end mills, reamers, and twist drills. This has significantly boosted our production capacity and overall efficiency.
Analytical Balance
An analytical balance is a highly precise laboratory instrument used to measure the mass or weight of samples with high accuracy and precision. It is commonly used in analytical chemistry, pharmaceuticals, and other scientific fields where precise measurements are required. Analytical balances typically have a readability of 0.1 milligrams (0.0001 grams) or less and are designed to minimize external factors that may affect the measurement, such as air currents and temperature fluctuations. They often use a draft shield to protect the sample from external influences and have a built-in calibration system to ensure accurate readings. Analytical balances can be operated manually or electronically, and some models are equipped with advanced features such as automatic calibration, data storage, and connectivity to a computer or other devices.
Analytical Balance,Analytical Scales,Laboratory Analytical Scale,Laboratory Analytical Balance
Lachoi Scientific Instrument (Shaoxing) Co., Ltd. , https://www.lachoinst.com
