ADFO flat drill streamlines flat-bottom hole processing in stainless steel part production
Vis Huang | OSG Shanghai
Drilling is one of the very first operations in hole-making. The quality of hole is especially critical when secondary operations, such as threading, is required. When working on expensive and time-consuming parts, choosing the most optimal drill for the application can make a significant impact to the bottom-line.
Tool selection is made based on a number of factors, including the configuration of the workpiece, material, cutting environment, the manufacturer’s specific requirement, etc. For parts and small batches with multiple materials, manufacturers in general prefer more versatile drills to simplify tool management. For medium to large quantity processing, application-specific drills are preferred as they are able to achieve higher efficiency and tool life.
Special holes, such as flat-bottom holes, can be a challenge for manufacturers who seek both quality and efficiency. For instance, in the drilling of inclined surfaces, a guide hole is usually required in order to minimize the shifting of the hole position. In cross-hole drilling, the drilled hole is typically finished with a milling cutter to minimize burrs. Although quality requirements are met with these conventional methods, multiple steps and tools are required, which hinder processing efficiency.
Sichuan Nick Seal Manufacturing Co., Ltd. located in Chengdu City in Sichuan province of southwestern China, was in seek of processing improvement in the production of stainless steel parts involving the drilling of flat-bottom holes. Founded in 2008, Sichuan Nick Seal Manufacturing’s key products and services include general part manufacturing, mechanical repair, pumps, valves, compressors and machinery manufacturing. As a long-time partner of OSG, Sichuan Nick Seal Manufacturing reached out to OSG applications engineer Yukai Zhang to improve the efficiency and hole quality of their stainless steel application.
The part in question is an element used for mechanical seal, which Sichuan Nick Seal Manufacturing has been producing for about two years using a Haas vertical machining center. It requires the drilling of six 5.2 mm diameter flat-bottom holes at a depth of 4 mm in SUS304. Tolerance must be maintained within +/- 0.1 mm. The average batch comes in 20 to 30 pieces. Sichuan Nick Seal Manufacturing used to manually grind conventional twist drills into flat drills to lower tooling cost. However, the lifespan of the handmade drills was short, and the product quality was unstable. Poor surface finish and occurrence of burrs were especially problematic. Upon a detail evaluation of the application, Zhang recommended OSG’s ADFO-3D carbide flat drill with oil hole for internal coolant to tackle the challenge.
The ADFO is the oil hole type offering from OSG’s recently expanded ADF multi-purpose flat drill series for inclined surfaces and counterboring applications. The ADF series is currently available in three styles to meet market demand – the ADF standard style, the ADFLS long shank style, and the ADFO with oil holes for internal coolant. With the additional oil hole configuration, the ADFO is designed to excel in stainless steel applications.
Machining a flat hole traditionally required the use of an end mill and a drill. OSG’s ADF carbide flat drill enables one-step drilling without requiring a starter hole to shorten machining time and simplify tool management. The ADF’s unique balanced point form improves precision and minimizes the shifting of the hole position. Its sharp cutting edge geometry results in low cutting force to minimize burrs even in thin plates. With a wide chip room configuration, trouble-free chip evacuation can be achieved. Furthermore, with the addition of OSG’s proprietary EgiAs coating, tool life can be prolonged with excellent heat and wear resistance. The ADF series is engineered for a wide variety of drilling applications including inclined surfaces, curved surfaces, counterboring, eccentric holes, thin plates, etc. It is suitable for materials such as carbon steel, alloy steel, hardened steel, cast iron and stainless steel.
In order to demonstrate the excellent chip separation capability and stability of the ADFO-3D carbide flat drill, Zhang set the program to machine 76 holes continuously on a scrap workpiece at a hole depth of 5 mm. The cutting condition was set at a cutting speed of vc 39.2 m/min (2,400 rev/min) and a feed per revolution of 0.063 mm.
Before the trial, the technical staff from Sichuan Nick Seal Manufacturing were hesitant with the parameters recommended by Zhang. However, knowing the capability of the ADFO flat drill, Zhang persuaded the production team.
As predicted, the result of the trial drew everyone’s attention with exceptional low cutting resistance and superior chip evacuation. After machining all 76 holes. The technicians from Sichuan Nick Seal Manufacturing could not be more satisfied with the efficiency, surface integrity of the hole, burrs of the hole, and the amount of wear on the tool.
Sichuan Nick Seal Manufacturing reports that the ADFO has accelerated operation efficiency by 2.5 times. The feed rate of the previous tool used was 60 mm/min. The ADFO was set at 150 mm/min.By employing OSG’s ADFO, Sichuan Nick Seal Manufacturing is able to maintain its high-quality standard while streamlining production process with fewer tooling and procedures to provide greater values to its clients.
For more information on OSG’s ADF multi-purpose flat drill series for inclined surfaces and counterboring applications