A measurement revolution
Unlike conventional CMM measurement methods, Renishaw’s 5-axis technology uses synchronised motion of CMM and head axes to minimise the machine’s dynamic errors at ultra-high measuring speeds.
What is 5-axis measurement?
Based on advanced head, sensor and control technology, Renishaw’s 5-axis measurement technology delivers unprecedented measuring speed and flexibility, whilst avoiding the speed versus accuracy compromises inherent to conventional techniques. It boosts measurement throughput, minimises lead times and gives manufacturers a more comprehensive appreciation of the quality of their products.
Unlike systems based around indexing heads or fixed probes, 5-axis motion enables the stylus to follow a continuous path around complex components without having to leave the surface to change stylus cluster or index the head. Controller algorithms that synchronise CMM and head motion produce an optimal tip path and minimise CMM dynamic errors.
5-axis measurement technology explained
In conventional measurement methods the CMM performs all the movements necessary to acquire the surface data. Acceleration induces inertial deflections in the machine structure, which in turn induce measurement errors.
Metrology system manufacturers have devoted years to develop techniques that reduce those dynamic errors, but there is an upper speed limit imposed by the machine and servo system stiffness, beyond which measurement cannot be taken with reliability.
5-axis measurement technology breaks through that limit by using an articulating head that moves in two rotary axes as it measures. This allows the CMM to do what it is best designed to do – move at constant velocity in a single vector while measuring. As the head is much lighter and more dynamic than the CMM, with a significantly better bandwidth, it is able to quickly follow changes in the part geometry without introducing harmful dynamic errors, which results in much faster surface speeds and hence shorter measurement cycles.
5-axis vesus 3-axis measurement throughput studies
Scanning – aero engine blisk
922% improvement in throughput
Bladed discs (known as ‘blisks’) present extreme access challenges and conventionally require numerous head indexes.
Renishaw’s 5-axis measurement dramatically reduces cycle times through continuous scanning of blade sections, blade surfaces and root profiles.
- 9 sectional scans, 8 longitudinal scans and 2 root profile scans per blade
- 1 scan of annulus profile
- 3-axis scanning at 10 mm/sec measurement time;
1 blade = 46 min, all 29 blades = 22 hours 11 min
- REVO at 200 mm/sec measurement time; 1 blade = 4 min 30 sec, all 29 blades = 2 hours 10.5 min
922% throughput increase
Scanning – cylinder head
690% improvement in throughput
Valve seat and guide measurement is one of the toughest measurement tasks in an automotive cylinder head. Using a helical scan, the REVO head gathers thousands of data points from which the height, diameter, seat width and form can be determined.
- 12 valve seats
- 12 valve guides
- 3-axis scanning at 15 mm/sec measurement time
= 29 min 13 sec
- REVO at 400 mm/sec and 50 mm/sec measurement time = 3 min 42 sec
690% throughput increase
Touch-trigger – valve block measurement comparison PH20 versus traditional motorised indexing head
300% improvement in throughput
We measured a valve block with a traditional motorised indexing head. We fitted a PH20 to the same CMM and measured the same features, with the same number of points on the same part. The CMM speed and acceleration settings were kept the same.
- 8 bores measured
- 3-axis motorised indexing head, measurement time = 1 min 52 sec
- With the PH20 5-axis touch trigger probe head, measurement time = 37 seconds
300% throughput increase for measurement process
- Before: 1 tip, 8 positions 4 minutes
- 1 tip, inferred calibration for all positions, 2 min 30 seconds
37.5% throughput increase for calibration process