In first and second parts of this article, methods for ACM panels installation ere pointed out. In this part ACPs fabrication instructions and methods will be introduced in order to prevent inappropriate result and aberrant damage.
Aluminum Composite Material Panels can be fabricated using wide variety of tools and machines. These tools and machines are classified into conventional ones and automated ones. Generally, automated machines enable high efficiency in large quantity analogous work. On the other hand, conventional machines and tools are more flexible and versatile. Supplying machines and tools for this purpose requires a costly and huge investment and the latter requires advanced skill for good work.
Following are the main machines and tools which are used for ACP fabrication purpose:
Saw Cutting:
Aluminum Composite Materials can be cut with various types of circular saws such as table saws, hand circular saws and panel saws. A suitable saw blade is a carbide-tipped blade for aluminum use. Suitable blade must have 255mm of diameter, 80-100 of teeth, 2.0-2.6mm of cut width, 10 degree of rake angle. Operating conditions should have 2,000-4,000 rpm rotation of saw blade and 10-30 m/min feed speed.
Instructions and notes for saw cutting:
- Do the cutting operation with the external side facing upward to prevent the panel from scratches and the protective film from pilling of.
- Remove cutting chips from ACP carefully after cut, to avoid dents during storage and assembly.
- Sharpen or replace the saw blade after it becomes dull to prevent large burr or distortion at the cut edge.
Shear Cutting:
A square shear permits and efficient sizing work. For different ACP thickness, clearance and rake angle are also different. For ACP with 3mm ALPOLIC thickness, clearance should be 0.04-01mm and rake angle should be 1 degree. For ACP with 4mm ALPOLIC thickness, clearance should be 0.04-01mm and rake angle should be 1.30 degree. For ACP with 6mm ALPOLIC thickness, clearance should be 0.2mm and rake angle should be 2.30 degree.
Trimming of Cut Edge:
Generally, a burr appears on both sides of the edges after saw cutting. After shear cutting, either a droop or burr appears on each edge. If the panel is installed with this condition, it is required to control the edge conditions.
- As it was pointed out in Saw Cutting section, we should keep the saw blade sharp enough to have proper edge.
- In Shear Cutting adjusting the clearance of the die is necessary. If further trimming of the cut edge is needed, the edge should be trimmed using a hammer, plane or sandpaper.
- In solid, metallic, sparking colors, deep trimming like chamfering may have an aesthetic effect. Use a trimmer with ball bearing chamfering bit or plane. In working with plane, a guide ruler will help to ensure a uniform edge.
Curving Cut:
Aluminum Composite Material can be cut in curving lines by hand router and trimmers. Jigsaws are also useful for cutting complex shapes. Use the guide template to stabilize this work.
Notes on guide template:
- Put the guide template on the external side of the ACP to do the routing work through the guide template.
- Remove the particles caught between the guide template and the ACP surface, to prevent scratches and dents.
U-Grooving:
ACPs can be fold after U-grooving in the backside. Two types of machines are available for U-grooving process. First is a circular cutter type and the second is a router type. The former includes hand grooving machines and panel saws, and the latter includes hand routers and CNC routers.
The typical U-groove shape suitable for ACM panels need to have 0.2-0.4mm of core. It is recommended 90-110 degree grooves for 90 degree bending.
Hand grooving Machines-They can groove ACPs. Use a cutter blade having the proper groove shape. A suitable cutter blade should have 110-120mm of outside diameter, 4 teeth, and carbide tip. Operation condition should have 5,000-9,000 rpm rotation and 5-20 m/min feeding speed.
Hand Router-It can groove both straight lines and curving lines. Use a custom router bit having the suitable bit and conditioning which is having 2-4 teeth and carbide tip and 20,000-30,000 rpm rotation and 3-5 m/min feeding speed.
Panel Saw- panel saw enable efficient and precise grooving. Typical conditions are having a cutter blade with 220mm outside diameter,8 teeth, carbide tip and operation with 2,500-5,000 rpm rotation and 30 m/min feed speed.
Folding:
After U-grooving, it is allowed to fold ACPs with folding jig. The typical folding procedure are as follows:
- U-groove: Leave 0.2-0.4mm core.
- Folding jig: Use a folding jig made of aluminum or steel angle.
- Fold: Use a jig nearly fits to the folding length.
- Support: Support with aluminum angle, if necessary.
Notes on folding:
- ACM panels should be fold on a flat and rigid worktable.
- The folded corner should have a suitable roundness of 2-3 mm in radius. If the roundness is too small, the coating may have crack on the folded corner.
- Cracks may occur the folding work is carried out at low temperature. Thus it is necessary to have folding work at 10 centigrade degrees or higher.
- Folding after U-grooving entails slight elongation. The elongation is 0.5-1 mm per fold. Pre-adjust the position of the grooving line in fabrication drawing.
Making Hole with Drill:
Making hole on ACM can be done with a hand drill or drill press, equipped with a drill bit, a hole-saw and a circle cutter. Making a hole from the external side will reduce the burr.
Punching and Notching:
Punching press can be used for notching and cutting out. The suitable clearance between punch and die is 0.1 mm or smaller. A small droop will appear at the edge which is punched. Using notching tool is also approved for removing the corner.
Bending with Press Brake:
Aluminum Composite Panels can be bent with press brake. The bend-ability depends on the thickness and the corner material. The smallest bendable radius depends on the thickness of the panel.
Notes on press brake bending:
- Smallest bendable radius means the limit which visible wrinkles appear on the ACP surface. Cracks will appear at a slightly smaller radius than this value.
- Use the top punch with an almost similar radius to the desired radius. If the radius is much smaller, it may cause the cracks to appear.
- When we carry out the bending work at a low temperature e.g. 15 degrees of Celsius, the coating surface may change to a haze-like appearance. Warm the panel to 20 degree or higher and the haze-like appearance will disappear.
CNC Router:
ACPs can be cut and grooved with CNC routers. As all the procedure are computer-controlled program, CNC router is suitable for repetition of analogous work. The suitable bit and operating conditions are the same as the hand routers.
Turret Puncher:
Turret puncher is also a computer-controlled, and can be used for perforation of Aluminum Composite Materials. The suitable clearance between punch and die is 0.1 mm or smaller. A small droop will appear at the punched edge.
Bending with 3-roll bender for ALPOLICs:
It is approved to use manual or electric –drive-3roll benders for bending ALPOLIC ACPs. The smallest bendable radius of ALPOLIC 4mm is approx. 300 mm in 2,500 mm long machines. The exact bendable limit depends on the bending roll diameter, roll length and the type of bending machine.
Notes on 3-roll bending:
- Prior to a bending operation, wipe the roll surface carefully.
- Remove any burrs at the ACM edge that may cause dents while rolling.
- Remove the cut particles stuck on ACM and smooth any wrinkles on the protective film which may cause dents.
- Do not constrict ALPOLIC panel between rolls. Extreme compression may cause a physical damage of the core. Adjust the clearance between rolls to be the panel thickness plus some allowance (approx. 0.5 mm).
- If a notch is desired in the panel, cut the notch after bending. Cutting the notch will result in a distorted curving.
- In most 3-roll benders, the curve near the edge tends to be straight. We can reduce this straight portion to some extent by overlapping another auxiliary sheet material and bending together with ALPOLIC ACM. If it is required a consistent curve near the edge, doing additional edge bending after regular bending is essential.
Other:
Water Jet Cutting – A lunge cut (piercing at the starting point) in water-jet cutting may cause a certain degree of de-lamination between the aluminum skin and the core material. Therefore, plunging at a disposable area or start at panel edge is needed. After penetrating through panel, water jet can cut the Aluminum Composite Material.
Laser Cutting – According to some approvable tests, so far it is concluded that Aluminum Composite Materials are not suitable for laser cutting, because the fumes generated from ACMs might harm the sophisticated optical instrument in the laser system.
