The new Kennametal asymmetric in-line borehole solution increases machining robustness, process speed and drill quality while reducing maintenance and handling of tooling.
Precision bore is a vital process in the manufacture of many critical components. The precision and finish of a multi-cranked crankshaft line directly influences the power and efficiency of an engine block, and the time required for the operation determines the benefits of the engine manufacturer. In many technical components, precision bores are essential to critical performance indicators. These bores must meet critical tolerances; The disadvantage is that the precision bore can be expensive and tedious, as a slight error may result in the discarding of expensive parts. Kennametal proposes as a solution a geometric and asymmetrical in-line boring bar, qualified by delighted users of true process revolution.
Unlike drilling, the bore is by definition a machining process in which the internal diameters are really realized with respect to the axis of the spindle. This process is most often carried out with the workpiece held stationary and the cutting tool progressing in the workpiece by turning, even if the bore is also effected with a cutting tool and an adjustable part.
Typically, bore applications include enlarging and finishing core, drilled or drilled holes, as well as profiled internal surfaces. The related operations, sometimes carried out at the same time as the bore, go through turning, dressing, chamfering, grooving and threading.
How it's made
For example, a small five-cranked inline engine block, requiring crankshaft bores. Traditional thinking for a multi-cranked operation, for example, involves a reamer with multi-section guide pads for the following suggested process (hereinafter referred to as Option 1.0):
- A pilot reamer completes the finishing of the first crankpin
- The multi-cut reamer is inserted and realizes the semi-finishing and the finishing of the cranks 2 to 5.
- The reamer is then retracted.
This process has the advantage of lending itself to horizontal and multiaxial CNC machining centers, without the need for a boring machine or special fastening devices. However, depending on the size of the workpiece, the machine tool must be sufficiently rigid, otherwise the quality will collapse dramatically. Also, inserting and removing the reamer on the finished bores must be done slowly and precisely, otherwise there will be marks of shrinkage and / or damage to the cutting edges.
There is a general machining option for this type of bore: the in-line bore (Option 2.0). The fundamental question to be solved is as follows: how, with lower diameters of holes, pass the cutting blades and the guide pads into the unfinished cranks?
Manufacturers of CNC machine tools have responded to this dilemma by using conventional in-line boring bars, providing their equipment with a possibility of "counter-bearings".
The process looks like this:
- The machining area of ??the machine tool lifts the motor unit
- The in-line boring bar is inserted through the component into a bearing at the opposite end
- The cylinder block is adjusted and held in position
- The bores of the crankshaft are semi-finished and finished
- The cylinder block is lifted and the boring bar, released
The process accelerates insertion and removal and the geometric quality of the finished bore is improved relative to the Bore Option 1.0 by the fact that the tool is supported at both ends. Reverse of the medal: the lifting functions require a specific CNC installation and control and the counter bearing required at the fastenings makes it impossible to do any additional face-up machining.
Multi-axis machine tools with tilting trays and / or tilting spindles combined with more advanced boring bars contribute to Option 2.1 of in-line boring with expandable guide pads where the process becomes the following:
- A pilot reamer is inserted and completes the finishing of the crank pin 5
- The component (or table of the machine) rotates by 180 degrees
- The axes X and Y of the machining center are adjusted to allow the eccentric insertion of the boring bar.
- The boring bar with its guide pads is centered in the crank pin 5.
- The guide pads are deployed
- Cranks 1 to 4 are semi-finished and finished
- The guide pads are reintroduced
- The boring bar is released off-center
Option 2.1 uses the multi-axis adaptability of the machine tool. It retains the benefits of Option 1.0 by eliminating the need for lifting or stopping function and Option 2.0 with support for both ends of the tool. Disadvantages: Complex internal mechanisms of this type of boring bar are expensive and can be difficult to manage. Insufficient lubrication may damage sensitive internal mechanisms and, in the absence of close supervision, the tool may become jammed or hang in the workpiece and damage the machine, attachment, tool Or the room.
An asymmetric solution
By working with the engine block department of a major automaker, Kennametal's engineering team has advanced the bore function with Option 3.0, the asymmetric in-line bore. This is an important step forward in terms of geometry, which reinforces the advantages of in-line drilling and boring while virtually eliminating the disadvantages of both techniques.
As with most advanced solutions, the basic principle is very simple. Normal guide diameters are made of solid material or made up of three or more guide pads, leaving no degree of freedom at the time of insertion and withdrawal at the bore wall. The Kennametal solution is based on guide pads with a configuration similar to that of a conventional guide plow reamer, except that the guide shoe, which is usually disposed at 180 ° to the cutting edge, has undergone a rotation giving Any latitude for entering and leaving the guide piece without passing through the rough bores. Thanks to this geometry, the bar is inserted into the raw bores along an eccentric trajectory.
The process then looks like this:
- A pilot reamer is inserted and completes the finishing of the crank pin 5
- The component (or table of the machine) rotates by 180 degrees
- The asymmetric boring bar is inserted eccentrically by means of the axes X and Y of the machining center
- The tool is moved to the center and realizes the simultaneous finishing of the cranks 1 to 4
-The tool is eccentric and quickly extracted
This asymmetrical in-line bore retains all the advantages of the previous on-line boring solutions: high-quality precision, supported at both ends, without requiring costly lifting functions, obstructive counter-bearings or critical mechanisms. It should also be added that the input and output movements can be executed at higher feed rates on conventional machining centers, thereby enhancing the efficiency of the process.
Of course, in the case of a Kennametal solution, the indexable pads proposed with the eccentric bore bar configuration are also very elaborate. The high-precision RI8 pads have 8 cutting edges with pre-defined clearances to ensure fast feed speeds. The diameter is adjustable with an accuracy of 1 micron. The high clamping force provided by the tapered locking screw compensates for any sagging effect.
The pads and the asymmetric boring bar are designed for mounting the pads directly into the body of the boring bar. This eliminates the need for cartridges as well as additional tolerances and space.
In short, this asymmetric in-line boring solution increases machining robustness, process speed and drill quality, reduces maintenance and tool handling while being compatible with CNC machining centers; An ideal solution for any manufacturer in search of process improvement.
? Kennametal nominated for the BMW 2014 Innovation Award
In November 2014, Kennametal Inc. announced that it was among the three recognized vendors of the BMW 2014 Supplier Innovation Awards in the "Productivity" category.
Kennametal, the only tooling supplier to be nominated for the award, has also been recognized for its partnership of more than 30 years with BMW. Among the reasons that led BMW to quote Kennametal for this honor is the new innovative tool that has increased the productivity of the engine blocks at the BMW Steyr plant in Austria. Kennametal assigns a team of technical solutions to working with BMW on such productivity improvements.
"We are honored to have been recognized among more than 200 suppliers at the BMW Supplier Awards," said Gérald Goubau, Vice President and General Manager of Kennametal Tooling. "This is a terrific affirmation and reminder of our mission to bring innovations that our customers value; This is what we strive to do on a daily basis. "
The BMW Group believes that innovation is the key to a company's economic success and competitiveness. Above all, mastering the challenges facing the automotive industry requires a high level of creativity and inventiveness. The BMW Group therefore recognizes its most innovative suppliers as key partners, playing an essential role in the successful implementation of new developments. The Supplier Innovation Award is intended to pay tribute to their achievements.
Precision bore is a vital process in the manufacture of many critical components. The precision and finish of a multi-cranked crankshaft line directly influences the power and efficiency of an engine block, and the time required for the operation determines the benefits of the engine manufacturer. In many technical components, precision bores are essential to critical performance indicators. These bores must meet critical tolerances; The disadvantage is that the precision bore can be expensive and tedious, as a slight error may result in the discarding of expensive parts. Kennametal proposes as a solution a geometric and asymmetrical in-line boring bar, qualified by delighted users of true process revolution.
Unlike drilling, the bore is by definition a machining process in which the internal diameters are really realized with respect to the axis of the spindle. This process is most often carried out with the workpiece held stationary and the cutting tool progressing in the workpiece by turning, even if the bore is also effected with a cutting tool and an adjustable part.
Typically, bore applications include enlarging and finishing core, drilled or drilled holes, as well as profiled internal surfaces. The related operations, sometimes carried out at the same time as the bore, go through turning, dressing, chamfering, grooving and threading.
How it's made
For example, a small five-cranked inline engine block, requiring crankshaft bores. Traditional thinking for a multi-cranked operation, for example, involves a reamer with multi-section guide pads for the following suggested process (hereinafter referred to as Option 1.0):
- A pilot reamer completes the finishing of the first crankpin
- The multi-cut reamer is inserted and realizes the semi-finishing and the finishing of the cranks 2 to 5.
- The reamer is then retracted.
This process has the advantage of lending itself to horizontal and multiaxial CNC machining centers, without the need for a boring machine or special fastening devices. However, depending on the size of the workpiece, the machine tool must be sufficiently rigid, otherwise the quality will collapse dramatically. Also, inserting and removing the reamer on the finished bores must be done slowly and precisely, otherwise there will be marks of shrinkage and / or damage to the cutting edges.
There is a general machining option for this type of bore: the in-line bore (Option 2.0). The fundamental question to be solved is as follows: how, with lower diameters of holes, pass the cutting blades and the guide pads into the unfinished cranks?
Manufacturers of CNC machine tools have responded to this dilemma by using conventional in-line boring bars, providing their equipment with a possibility of "counter-bearings".
The process looks like this:
- The machining area of ??the machine tool lifts the motor unit
- The in-line boring bar is inserted through the component into a bearing at the opposite end
- The cylinder block is adjusted and held in position
- The bores of the crankshaft are semi-finished and finished
- The cylinder block is lifted and the boring bar, released
The process accelerates insertion and removal and the geometric quality of the finished bore is improved relative to the Bore Option 1.0 by the fact that the tool is supported at both ends. Reverse of the medal: the lifting functions require a specific CNC installation and control and the counter bearing required at the fastenings makes it impossible to do any additional face-up machining.
Multi-axis machine tools with tilting trays and / or tilting spindles combined with more advanced boring bars contribute to Option 2.1 of in-line boring with expandable guide pads where the process becomes the following:
- A pilot reamer is inserted and completes the finishing of the crank pin 5
- The component (or table of the machine) rotates by 180 degrees
- The axes X and Y of the machining center are adjusted to allow the eccentric insertion of the boring bar.
- The boring bar with its guide pads is centered in the crank pin 5.
- The guide pads are deployed
- Cranks 1 to 4 are semi-finished and finished
- The guide pads are reintroduced
- The boring bar is released off-center
Option 2.1 uses the multi-axis adaptability of the machine tool. It retains the benefits of Option 1.0 by eliminating the need for lifting or stopping function and Option 2.0 with support for both ends of the tool. Disadvantages: Complex internal mechanisms of this type of boring bar are expensive and can be difficult to manage. Insufficient lubrication may damage sensitive internal mechanisms and, in the absence of close supervision, the tool may become jammed or hang in the workpiece and damage the machine, attachment, tool Or the room.
An asymmetric solution
By working with the engine block department of a major automaker, Kennametal's engineering team has advanced the bore function with Option 3.0, the asymmetric in-line bore. This is an important step forward in terms of geometry, which reinforces the advantages of in-line drilling and boring while virtually eliminating the disadvantages of both techniques.
As with most advanced solutions, the basic principle is very simple. Normal guide diameters are made of solid material or made up of three or more guide pads, leaving no degree of freedom at the time of insertion and withdrawal at the bore wall. The Kennametal solution is based on guide pads with a configuration similar to that of a conventional guide plow reamer, except that the guide shoe, which is usually disposed at 180 ° to the cutting edge, has undergone a rotation giving Any latitude for entering and leaving the guide piece without passing through the rough bores. Thanks to this geometry, the bar is inserted into the raw bores along an eccentric trajectory.
The process then looks like this:
- A pilot reamer is inserted and completes the finishing of the crank pin 5
- The component (or table of the machine) rotates by 180 degrees
- The asymmetric boring bar is inserted eccentrically by means of the axes X and Y of the machining center
- The tool is moved to the center and realizes the simultaneous finishing of the cranks 1 to 4
-The tool is eccentric and quickly extracted
This asymmetrical in-line bore retains all the advantages of the previous on-line boring solutions: high-quality precision, supported at both ends, without requiring costly lifting functions, obstructive counter-bearings or critical mechanisms. It should also be added that the input and output movements can be executed at higher feed rates on conventional machining centers, thereby enhancing the efficiency of the process.
Of course, in the case of a Kennametal solution, the indexable pads proposed with the eccentric bore bar configuration are also very elaborate. The high-precision RI8 pads have 8 cutting edges with pre-defined clearances to ensure fast feed speeds. The diameter is adjustable with an accuracy of 1 micron. The high clamping force provided by the tapered locking screw compensates for any sagging effect.
The pads and the asymmetric boring bar are designed for mounting the pads directly into the body of the boring bar. This eliminates the need for cartridges as well as additional tolerances and space.
In short, this asymmetric in-line boring solution increases machining robustness, process speed and drill quality, reduces maintenance and tool handling while being compatible with CNC machining centers; An ideal solution for any manufacturer in search of process improvement.
? Kennametal nominated for the BMW 2014 Innovation Award
In November 2014, Kennametal Inc. announced that it was among the three recognized vendors of the BMW 2014 Supplier Innovation Awards in the "Productivity" category.
Kennametal, the only tooling supplier to be nominated for the award, has also been recognized for its partnership of more than 30 years with BMW. Among the reasons that led BMW to quote Kennametal for this honor is the new innovative tool that has increased the productivity of the engine blocks at the BMW Steyr plant in Austria. Kennametal assigns a team of technical solutions to working with BMW on such productivity improvements.
"We are honored to have been recognized among more than 200 suppliers at the BMW Supplier Awards," said Gérald Goubau, Vice President and General Manager of Kennametal Tooling. "This is a terrific affirmation and reminder of our mission to bring innovations that our customers value; This is what we strive to do on a daily basis. "
The BMW Group believes that innovation is the key to a company's economic success and competitiveness. Above all, mastering the challenges facing the automotive industry requires a high level of creativity and inventiveness. The BMW Group therefore recognizes its most innovative suppliers as key partners, playing an essential role in the successful implementation of new developments. The Supplier Innovation Award is intended to pay tribute to their achievements.