Please click on the cover to view
Laser & Waterjet Profiling
Register here for a free monthly edition of the magazine
Subscribe here to receive our free newsletter for a monthly round-up of the latest news and features
Like many other companies obsessed with quality, Six Sigma and other proven methodologies are essential at ITT’s Goulds Pumps Division. But when it comes to implementing new technologies, product engineer Robert Kilmer sometimes veers off the beaten path. As Solutions learns, he has found that 3D scan data processing and inspection using Geomagic software is a critical ally in opening up new and productive ways of analysing product quality.
Geomagic software uses 3D scanning and scan data processing technologies to close the loop between physical products and their digital representations. The key component for Goulds Pumps is Geomagic Qualify – 3D inspection software that enables users to perform a complete inspection of every type of shape and feature that characterises an object, ultimately saving time and increasing inspection accuracy.
Over the last few years, Goulds Pumps has had its share of breakthroughs, including new processes to improve impeller balance and determine foundry process variation.
Throwing out the book
During the project to improve impeller balance, Mr Kilmer and his team deviated from standard practice that combines 3D scan data processing with CAD for quality assurance.
“We took a big departure from the conventional approach outlined in recent publications where all processes seem to start or end with a CAD model,” he says. “We threw that book out the window and we only use the Geomagic models – there are no CAD models used or created anywhere in the process.”
The balance of impellers affects the operation and lifespan of every pump and the challenge for Goulds Pumps was to reduce the time to balance the impellers and increase material flow.
The standard inspection method would have called for the company to scan the impeller, convert the data from point clouds to polygons to NURBS surfaces using Geomagic software, and measure the resulting digital model against the nominal 3D CAD model. Mr Kilmer’s team tried that and even though it only took hours compared to the days it would likely take using traditional CMM methods with 2D drawings or 3D CAD, it was still too lengthy a process. “For the purpose of understanding the factors that affect balance this simply took too long – especially considering the large number of impellers we wanted to study.”
From hours to minutes
The process that Goulds Pumps came up with is deceptively simple and takes about 10 minutes for each impeller. Scans of the same impeller are imported into Geomagic Qualify twice, so that two copies of the scan exist in the same 3D space. Within Qualify, one object is rotated 180° degrees, then a procedure called ‘fine adjustment best fit’ is performed on the two copies. After that, a 3D comparison is made. Differences that affect balance are visible immediately.
At the time of this project, Goulds Pumps was analysing around four impellers a day so the accumulative time savings over the course of a month using the new process amounted to several days. Those savings multiplied over the life of the project, which lasted about 18 months.
“It’s a very simple process that reflects the essence of what we need to measure – rotational symmetry,” Mr Kilmer adds. “The underlying message is that 3D scanning and scan data processing can have significant value for companies and industries even if they don’t rely on 3D CAD models. The greater volume of analysis in less time leads to faster learning curves. Trends are more observable when you can look at many units in succession as opposed to one at a time.”
Besides speed, the new process delivered the ability to differentiate between casting induced unbalance and machining induced unbalance.
“This is unprecedented,” says Mr Kilmer. “We learned that machining induced unbalance is relatively uncommon, but there is a big advantage in seeing and demonstrating it when it does happen. We are now able to use Geomagic Qualify visualisations to improve our suppliers’ machining processes and optimise part balance.”
A breakthrough in wall thickness
The ability to identify wall thickness variance is another significant breakthrough for Goulds Pumps. Variations in wall thickness are caused by differences in the shapes of the casting, mould and pattern tool. Comparing scans of these three related objects within Geomagic Qualify enables Goulds Pumps to pinpoint the magnitude and source of variations. The process is said to be so accurate that it can measure small differences in wall thickness due to molten metal flowing into and filling sand moulds.
“Geomagic Qualify clearly shows that sand castings are not necessarily perfect replicates of the moulds from which they are produced,” Mr Kilmer observes. “We can now measure variation and its source down to a level at which it is not economically viable to reduce any further. There is a huge value in knowing that we can control all important factors and be aware of other elements that we might not want to control for cost/benefit reasons.”
The ability to quickly and accurately make direct measurements and comparisons of wall thickness has extended to other projects at the New York headquartered company. It is helping, for example, to uncover potential production issues with older pattern tools that do not have associated 3D CAD models.
“We can scan the tooling pieces, assemble them electronically in Geomagic Qualify to create a polygon model of the casting and then compare the model to a scan of an actual production casting. Using several Geomagic Qualify analysis processes along the way, we can identify all possible tooling issues and differentiate them from process induced issues.”
Pervasive quality impact
Mr Kilmer says that although many of the benefits of 3D scanning and scan data processing are difficult to quantify by numbers, they are nonetheless concrete.
“The biggest qualitative measure is our reliance on these technologies throughout ITT/Goulds Pumps,” he affirms. “Geomagic Qualify has allowed us to see foundry process variation that we could not see previously because of the complex geometries required for hydraulic designs. We can also ‘see through’ the complexity of the pattern tooling and the sheer number of factors that influence foundry operations. With this technology, we can focus our efforts on the factors that directly influence the quality of our castings.”
He points out one other qualitative measure: ITT recently awarded the Seneca Falls Foundry where he works, the Gold Ring of Quality – the highest quality recognition within the company. “It is due in large part to lots of hard work by the foundry staff,” Mr Kilmer concludes. “But I also believe that 3D scan data processing technology contributed to that award.”
Headquartered in New York and with a service and support network that spans the globe, Goulds Pumps manufactures quality industrial pumps and parts for the chemical, pulp and paper, mining, mineral processing, oil and gas, and power industries.