Jack Ubersax
Aluminum
- Joined
- Mar 5, 2005
- Location
- Wilbraham, MA
There are several important aspects that W/S engineers looked into in proper depth prior to finalizing the design of the SC bed-type machines.
For example, for a given spindle height, the bed ways can be spaced further apart on a slant bed then on a vertical bed machine. Too great a slant would, however, cause tools to interfere with the position of the operator at the machine. Studies showed that a 20 degree slant allows wider way spacing without unduly widening the machine or causing any hazard to the operator with tool indexing.
The wider way spacing of the slant bed keeps the end turret cutting forces continually between the ways, giving greater stability. This will be shown in the cutting ability of the machine, both in terms of the surface finish during light accurate cuts and in the machine's great stability during the heavy roughing cuts that the W/S machines have been known for.
In the slant bed configuration, gravity forces settle the slide on the rectangular ways and allows them to act in exactly the same manner as V ways, assuring good guiding ability.
The slant bed design allows the placement of all three ways on its wide front surface, providing support for both the end turret and the side turret. The cutting forces act on the heavy saddle and carriage to reinforce the way loads and keeping them down onto the ways.
The vertical bed configuration, which had to be looked at briefly as a possible alternative, was discarded in the engineering investigation and development phases. Major disadvantages seen were that its narrower way spacing caused more forces to fall outside the lower way, especially on large diameter cuts. On a facing cut this could cause a shift in the controlling way surface as cutting forces crossed over this way. Also, the vertical bed required the third way to be placed on the top surface of the bed, away from the cutting action. That would result in a two piece saddle construction to reach that top way, and would introduce another joint directly in the path between the cutting tool and the way reaction forces. This, in an area where maximum stiffness and rigidity are needed for both accuracy and cutting ability.
Also, the slant bed allows the side turret to pull away from the work area for use of crane loading, while the vertical bed forces the turret to remain above the spindle centerline, which could interfere with workpiece loading.
It should be recalled that some of W/S competition talked about advantages of their slant bed machines, when in fact, they had no such thing! What they were really selling were flat bed machines upon which they placed a slanted slide. There were several Japanese builders who employed this concept in their early years.
For example, for a given spindle height, the bed ways can be spaced further apart on a slant bed then on a vertical bed machine. Too great a slant would, however, cause tools to interfere with the position of the operator at the machine. Studies showed that a 20 degree slant allows wider way spacing without unduly widening the machine or causing any hazard to the operator with tool indexing.
The wider way spacing of the slant bed keeps the end turret cutting forces continually between the ways, giving greater stability. This will be shown in the cutting ability of the machine, both in terms of the surface finish during light accurate cuts and in the machine's great stability during the heavy roughing cuts that the W/S machines have been known for.
In the slant bed configuration, gravity forces settle the slide on the rectangular ways and allows them to act in exactly the same manner as V ways, assuring good guiding ability.
The slant bed design allows the placement of all three ways on its wide front surface, providing support for both the end turret and the side turret. The cutting forces act on the heavy saddle and carriage to reinforce the way loads and keeping them down onto the ways.
The vertical bed configuration, which had to be looked at briefly as a possible alternative, was discarded in the engineering investigation and development phases. Major disadvantages seen were that its narrower way spacing caused more forces to fall outside the lower way, especially on large diameter cuts. On a facing cut this could cause a shift in the controlling way surface as cutting forces crossed over this way. Also, the vertical bed required the third way to be placed on the top surface of the bed, away from the cutting action. That would result in a two piece saddle construction to reach that top way, and would introduce another joint directly in the path between the cutting tool and the way reaction forces. This, in an area where maximum stiffness and rigidity are needed for both accuracy and cutting ability.
Also, the slant bed allows the side turret to pull away from the work area for use of crane loading, while the vertical bed forces the turret to remain above the spindle centerline, which could interfere with workpiece loading.
It should be recalled that some of W/S competition talked about advantages of their slant bed machines, when in fact, they had no such thing! What they were really selling were flat bed machines upon which they placed a slanted slide. There were several Japanese builders who employed this concept in their early years.
