Let’s start from the beginning Marco, what is the first step of our production?
First of all, CMS workshop is able to manufacture many kinds of components, thanks to the high competence of its operators and its fleet of machinery.
Most part of the production starts from two different types of raw material: metal sheets and raw bars.
Let’s assume to buy metal sheets, what happens next?
We mainly use large plates in AISI 304 or 316L stainless steel alloys, which are then cut by laser, a machine able to make precise cuts on thicknesses up to 20 mm.
The second phase is usually bending, it is possible to perform bends with a maximum width of 3 m and a maximum thickness of 10 mm, or up to 15 mm for more compact metal sheets.
And should we work on raw bars?
We would start from bars of different material (AISI 304, 316L, aluminium, construction and tempering steels) and different sections and dimensions (square, rectangular, round section) and we would get, by cutting, rough pieces of various sizes.
On them, we could perform different kinds of machining: circular section bars, with a diameter up to 600 mm and a length of 2100 mm can be processed in Turning Dept., where it is possible to obtain axial symmetrical machining by manual or CNC lathe, or more complex performances through hybrid machines able to perform both turning and milling during the same machining cycle. Bar pieces with a rectangular or square section are processed in Milling Dept.: here a wide range of machines with three, four or five axes, of different sizes and powers, allow the machining of both very small components with extremely small tolerances and very large ones, up to 3000 mm in length, with extreme rapidity and automation, thanks to the use of multipallet milling machines and robotic tool change system.
What happens at this point?
The components processed in the machine can be welded in our welding stations. We use both manual and robotic TIG/MIG technology. It is very important to underline that all our welding operators are skilled and certified according to UNI EN ISO 9606-1 for steel alloys and UNI EN ISO 9606-2 for aluminium alloys with reference to manual welding, and UNI EN ISO 14732 with reference to robotic welding. Welding is a very complex process where manual dexterity still plays a key-role.
How do we make sure that all processes have been carried out in quality?
At the end of each welding, we carry out visual checks in order to verify quality and, for welds that must guarantee tightness, we make checks with helium, water, air or penetrating liquids, to verify the absence of cracks or porosity, in accordance with the UNI EN ISO 9712: 2012 standard.
Then, the semi-finished product passes into Adjustment/Deburring Dept.: here it is possible to remove any residual part from the previous processes, to perform bevels, countersinks and threads that it was not possible to perform on the machine. In addition, there are manual satin finishing stations and a dedicated robot for very large components, up to 2300 mm in length.
The mechanical parts manufactured by CMS also have a very high visual quality, they look like jewels. How is this kind of finishing achieved?
For stainless steel components it is possible to perform surface treatments, such as pickling (to remove contaminating elements from surfaces as well as removing visual traces caused by welds’ heat), electropolishing (to improve surfaces quality, reducing roughness and possible dirt), and passivation (to reduce corrosion in critical atmospheres).
What is the final stage of the process?
Once each process has been completed, the component reaches Testing Dept. for visual checks, surface finishing control and tolerances analysis. These checks can be performed manually, or through specific automatic machines placed in a suitably air-conditioned room: here, we constantly monitor the thermal and hygrometric conditions in order to avoid any alterations during checks and therefore guarantee precise dimensional checks.
You have described all the possible stages of machining. We close this interview with a personal opinion. What is the aspect that most distinguishes our company?
What makes it technologically better than its competitors?
Among subcontracting companies, CMS certainly stands out for its ability not only to join projects that have already been finalized, but also to perform optimizations and entire redesigns on orders in progress.
For example, a few months ago an important customer asked us for a redesign and a general optimization of an entire machine, providing us just some technical specifications such as maximum dimensions and generic layout.
This request involved many sectors of our workshop, in particular metal sheets, bending and welding areas, putting both Technical Dept. and the involved operators through the wringer. Nevertheless, it has shown above all that CMS has a very great potential and important skills to offer, when it is necessary to carry out very complex and atypical projects.
Many thanks Marco!