As shown in the image above, a thermoforming drill can handle this task.
Thermoforming drilling is a chipless machining technology that creates holes and bushings in a single pass on thin metal sheets or tubes, completely replacing the process of welding (riveting) nuts onto thin-walled workpieces.
Watch a demonstration video.
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Using thermoforming drilling technology, bushings or clear holes can be easily formed on thin-walled parts with a wall thickness of less than 12mm. The thickness of the bushing or clear hole can be up to four times the original material wall thickness, with hole diameters ranging from 1.8mm to 32mm.
Thermoforming drills are made of wear-resistant, high-temperature-resistant carbide materials. When the tool contacts the workpiece, the high rotational speed (1000~4000 rpm) and appropriate axial thrust (feed force) cause intense friction between the drill bit and the metal, instantly reaching a temperature of 600~800℃. The metal in the vicinity of the drill bit softens rapidly, and with continued axial pressure, bosses and bushings approximately 3~5 times the thickness of the original sheet metal are quickly extruded onto the upper and lower surfaces of the workpiece. The entire process takes only 2-6 seconds.
Tapping is performed using a tap.
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For machining requiring smooth connecting surfaces or chamfered holes, a flat drill bit can be used to remove bosses formed on the workpiece surface. Bushings can be used as bearing supports, fork throat welds, etc. The threads are extruded, resulting in threads that can withstand higher tensile and torsional forces.
Machining Process Summary:
Step 1
The thermoplastic drill just contacts and positions itself on the material, then presses it down with high axial force and speed.
Step 2
The applied pressure and speed generate the required frictional heat of approximately 600°C, plasticizing and shaping the material. The thermoplastic drill penetrates the material within seconds.
Step 3
The thermoplastic drill extrudes the metal from both horizontal and vertical directions, moving the material downwards and creating a bushing. As the thermoplastic drill penetrates the metal, the feed pressure gradually decreases while the feed speed gradually increases.
Step 4
Now, the thermoplastic drill has formed a bushing. Material fed in the opposite direction is extruded and formed into a frustum suitable for sealing. This frustum can be removed in the same operation using a flat-head drill bit with a cutting edge at the drill bit's cutting edge.
Step 5
The formed bushing can be immediately tapped without chips using an extrusion tap, without storage. Cold extrusion tapping increases material hardness.
Step 6
Result: A connection capable of withstanding high loads and torques. No drilling, subsequent riveting, or welding of nuts is required.
Application Examples:
Machining Parameters and Process Demonstration:
Hot melt drilling can be used with almost all thin-walled metals (excluding tin or zinc), such as: common steel, stainless steel, low carbon steel, aluminum, copper, brass, bronze, titanium alloys, and various other ductile workpiece materials, and can also process electroplated workpieces.
