Monday, December 22nd, 2014
Sheet metal 3D model of an aluminium enclosure and cover
This sheet metal fabrication project for several different LED display cases started with a 3D model created in Radan sheet metal CAD/CAM software. All the information for the size of the cases, material thickness and holes positions was taken from our customers 2D DXF drawings. We used many of the inbuilt features within the Radan software to speed up the handling of corner conditions for preparing the joints ready for welding fabrication. We could even try the fit of the cover on the body of the cases, alignment of fixing holes and the ease of inserting the bushes and studs within the software to ensure they would fit once manufactured, welded and powder coated.
Folded aluminium sheet metal cases
Once the 3D model had been unfolded and tooled up and a sheet nest created within the software a CNC program was prepared that was used to laser cut the cases from sheets of 2mm thick 5251 aluminium alloy sheet. The cases were folded up on one of our Edwards Pearson 2.5M long CNC press brakes and you can see just how well the software can calculate the size of the developed blank so that it can be folded up without any gaps in the welded seam. The 3D model was created with the correct overlap of gauges at the joint needed by the welders as a weld preparation to enable the weld bead to penetrate the material gauge for a strong seam weld. The larger the component or more expensive the material the more of an advantage it is to be able to go straight into manufacturing without any trials and wasting materials with samples and CNC program adjustments.
TiG welding the aluminium cases corner joints
Unfortunately it’s very difficult to show clearly someone TiG welding due to the brightness of the light given off when the welding arc is struck on the parent metal. You do get a good idea of the processes needed to weld the joints from this image and the others shown here. The welder can only view the welding process through a special glass shield within the welding helmet that is light sensitive and can react to the brightness created of the weld arc darkening the glass and protecting the welders eyes during the whole welding fabrication process.
Aluminium sheet metal welded fabrication corner joints
When the welding is being carried out it’s important to penetrate through the gauge of the aluminium to get a strong joint. It’s also necessary in this case as the fabricated joints have to be cleaned off smooth and if the welder doesn’t penetrate right through the joint all the weld strength would be removed when the outside of the joint is ground back which could lead to cracks appearing after fabrication. Although the weld looks messy at this stage it will be perfect once it has been cleaned off as the image shows in the final manufacturing stage.
Cleaning up aluminium welded joints
Once all 4 corners joints were welded they could be cleaned up to produce a smooth finish. At this stage they have been ground down to the parent metal and then they will have an orbital sanded finish before being powder coated with then no visible joint lines seen at all. If you have an aluminium sheet metal welded fabrication project that you need manufacturing please give us a call and we will be happy to price it up for you.