St Bernard Composites saves 4% material with JETCAM high performance nesting
St Bernard Composites, based in Farnborough, UK, provides composite engineering services to the aerospace industry. Founded in 1961 they were cutting composites by hand up until 2000. Craig Dewar, Director, noted; "We used to cut the material with scalpels or scissors, which was very labour intensive and did not give the best yield out of the material. We decided to invest in the Exact cutting machine as we saw that we would achieve improvement in yield and a faster throughput."
The Exact cutting machine was installed in 2001, along with a CAM system provided by the machine manufacturer; however it soon became apparent that while cutting time and quality improved there were bottlenecks before and after the cutting process. Said Craig; "The CAM system was essentially a CAD package with a nesting module on rather than a dedicated nesting system, and as a result the automatic nesting never truly worked. Nests were therefore created manually, so the lead time from DXF through to actually cutting the job was often four weeks. "
A bottleneck was also identified in unloading the plies once they had been cut, so in 2003 St Bernard decided to invest in a Zund knife cutter with conveyor table. Once a section of the nest has been cut the conveyor moves the material down, allowing the operator to unload the plies while the machine continues to cut the rest of the nest. Craig added; "Although we could deal with longer nests we were not using dynamically generated nests at that time. We had an engineer manually nesting plies full time, which is purely a trial and error process. Every time we had to make a change we had to manually redo the nest, which in itself is open to error. In composites there are a number of factors that are constant, such as international availability of carbon fibre, which is on allocation. We decided to look around at other nesting software, initially highlighting three and quickly narrowing this down to two, one of which was JETCAM."
During the evaluation process St Bernard provided both vendors with a series of plies which they asked them to nest. The results were then compared to their most efficient manually created nests. "JETCAM outperformed the competitor by at least 2% on every occasion with a typical figure of 4%. Our throughput of material on the Zund alone is around £50-60k per week, so a saving of 4% is significant, not only in financial but also in yield terms. We challenged JETCAM on these figures, as some of the parts on the competitor's nest were actually overlapping. JETCAM were able to substantiate their figures by spending a day on-site with us to recreate the nests live. The whole experience was very positive and proactive, and they were prepared to give a generous amount of information even though at this stage we had not awarded the contract."
In 2006 St Bernard chose to standardise on JETCAM Expert, purchasing two licenses, each with postprocessors for both machines and JETCAM's free-form high performance nesting module. A license of JETCAM Orders Controller was also purchased to provide external management of JETCAM's order lists. Craig noted initial concerns regarding JETCAM's ability to drive the Zund machine; "We had a bad experience with a previous CAM supplier that said they could drive a machine, so were sceptical when JETCAM said that they would be able to write a postprocessor for the Zund, however our experience was we pretty much plugged it in and it worked straight away."
Training was performed on-site. Craig was impressed with the feedback that he received from his staff; "Although I was not present during the training I questioned the staff who had been trained and they were able to clearly demonstrate they understood how the software worked, which clearly helped the implementation process. That in itself was pretty straightforward. We simply imported our DXF files and then set about structuring our nests. We were able to start switching over to JETCAM quite quickly. As a result we saw benefits pretty early on. "
What was immediately noticeable was the dramatic reduction in time from DXF to cut ply. Pierre Engrand, Project Engineer commented; "We are using Single Component Automatic Processing (SCAP) to process DXFs and this is saving us literally weeks. Each DXF was taking anywhere up to 20 minutes previously to import, clean and apply profiling information before nesting. Now SCAP does this all automatically. We can also create nests dynamically if we need to, for example if we have to remake some plies."
The handling properties of composites can differ greatly, with materials such as BMI carbon, costing $93 per square metre, requiring a slow cut as the material can fray. JETCAM Expert has the ability to specify the cutting speed, which improves the quality of the cut and reduces material scrap. On materials where the cutting characteristics allow, the blade speed has actually been increased, giving an additional speed benefit. Facilities such as 'continuation of cut after reposition' make further use of the conveyor system on the Zund machine and allow for plies that are potentially larger than the machine bed size to be run. Where the material properties allow, common line cutting is also used to reduce material waste by using a single cut to separate plies.
In addition to the savings seen on the shop floor, the sales department has also benefited from the installation of JETCAM Expert. Material utilisation and runtime estimation are used to produce much more accurate quotes. This has been so effective that in 2007 St Bernard purchased a third license of JETCAM Expert exclusively for this purpose.
In the twelve months that St Bernard Composites has been using JETCAM they have seen a rapid return on investment, with initial costs recouped within 6 months. JETCAM are working with St Bernard to develop a material management module with a view to integration into their MRP system.
Support requirements have also been minimal. Craig noted; "I am not aware of us having to call on technical support at all. JETCAM does what it says on the can. It's in, it's working and it's trouble-free. That means that we are focused on using the software, not worrying about problems with it."
Craig finalised; "We operate in an industry that is driven by cost downs. When we sign long-term contracts with our customers we often have to commit to cost reductions over the period of the contract, which is difficult in a supply chain restricted by its raw material, and where its prices are not negotiable. The only area where we can achieve this is by finding efficiencies internally, and JETCAM has contributed to our ability to do that."
· St Bernard can now create dynamic nests as opposed to manually nesting plies
· Single CAM system driving both machines
· Process from DXF to cutting reduced from 4 weeks to 2-3 days, mainly due to automatic nesting
· Using SCAP to automatically apply profiling information to plies
· Control over the knife speed gives better quality finish on materials prone to tearing and has reduced production waste
· Where material properties allow, the knife speed has been increased to reduce overall cutting time
· Saving 'weeks' per year as profiling information is now applied automatically
· Providing an average of 4% saving on material over manually nested parts and at least 2% better than the closest competitor
· Users fully trained within three days
· Minimal support requirement
· System paid for itself within first 6 months of purchase
· Additional license purchased to improve quoting accuracy
· Material management module being developed
Machines Driven by JETCAM:
• Zund Knife Cutter
• Exact Knife Cutter
• JETCAM Expert Premium
• Auto nesting module with Free-form high performance nesting
• JETCAM Orders Controller
Press release issued by JetCam International s.a.r.l. on July 20, 2007
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