The hot stamping of the polymer was studied to improve product quality. The finite element method (FEM) was used to analyze the embossing step, as per the product quality we can take the steps cooling and demolding. The numerical simulation results show that profile precision is largely influenced by the topological structure of the mold during the embossing step. Inadequate holding time will result in low pattern fidelity. Inappropriate demolding temperature could induce large thermal stress at the bottom of the micropattern while keeping imprint pressure during the cooling step will aggravate this phenomenon. Fracture, necking and pattern distortion can easily be induced by adhesion between the polymer and the mold when high aspect ratio patterns are demolded. The hot embossing process was optimized and an improved hot embossing system with an automatic demolding device was designed based on the simulation analysis. Successful fabrication of fine patterns with a high aspect ratio verified the improvements.
In here we discuss the steps of how the embossing applying on leather material. You can create a relief design by either pressing of stamping a metal shape into unfinished leather. If you don’t have leather tools, choose the clamping method and if you want to invest in a leather design set, you should try the second method.
Clamping Leather
1. Take unfinished leather at a craft supply store. Embossing doesn’t work on pre-treated clothing or accessories.
2. Find a metal leather stamp, and use a charm or purchase a leather stamp in the design of your choice. You can order custom leather stamps through sellers.If you use a metal charm, make sure it has cut edges, rather than a tapered design. It will make your shape appear more pronounced in the leather.
3. First, smooth your unfinished leather section onto a worktable. The front side should be facing up. It must be near the edge of a table on which you can hook a strong C-clamp.
4. Dampen a sponge. You don’t want it to be sopping wet, so squeeze it out several times.
5. Brush the leather with the sponge in one even layer. Move the leather so that it can fit under the clamp.
6. Place the flat metal stamp or metal object on the leather where you want the embossed design to be.
7. Set the top foot of the C-clamp in the center of the metal object. Crank the clamp until it is clamped as far as it will go.
8. Remove the C-clamp after 20 minutes. Seal the leather with leather finish, if you want to improve the durability of the design and surface of the leather.
Stamping Leather
1. Take a leather stamping set. Buy 3-D stamps with a cylinder that can be inserted into any of the flat stamps. You can order custom stamps online or start with a set of alphabet stamps. Make sure the metal cylinder will match your stamps. The cylinder is the piece you use to pound the shape of the stamp into the leather.
2. Place your unfinished leather on a flat worktable. Make sure the front of the leather is facing up. Decide where you want to emboss your design.
3. Clean the leather surface with a damp sponge. If the water changes the color of the leather drastically, wait for it to dry a little.
4. Place the metal stamp on your leather where you want the design to be.
5. Place the metal cylinder into the center of the metal stamp. Hold it firmly with one hand.
6. Hit on the metal stamp several times with your wooden mallet. Be careful not to move the stamp while you hit it. You can pick up the stamp, see if the impression is inlaid deep enough and align it for stamping again.
The hot stamping of the polymer was studied to improve product quality. The finite element method (FEM) was used to analyze the embossing step, as per the product quality we can take the steps cooling and demolding. The numerical simulation results show that profile precision is largely influenced by the topological structure of the mold during the embossing step. Inadequate holding time will result in low pattern fidelity. Inappropriate demolding temperature could induce large thermal stress at the bottom of the micropattern while keeping imprint pressure during the cooling step will aggravate this phenomenon. Fracture, necking and pattern distortion can easily be induced by adhesion between the polymer and the mold when high aspect ratio patterns are demolded. The hot embossing process was optimized and an improved hot embossing system with an automatic demolding device was designed based on the simulation analysis. Successful fabrication of fine patterns with a high aspect ratio verified the improvements.
Working Principle of Embossing on a leather material.
Producing high-frequency current from a 3 phase supply and heating the stamping material by applying pressure on metal by manually or automatically. In here we discussing how this will happen.
The material used for the circuit for making high-frequency current.
1. Power – 3 phase voltage as supply. Phase is connecting to the contactor and the neutral is connecting in machine body.
2. Contactor in the 32A 230V coil – for switching the circuit.
3. Valve – opening the circuit for passing the high-frequency current to stamping material. This is high volt filament lamps for passing this High-frequency current to stamping material. And the cathode and Anode (+Ve and –Ve) terminals are connected together. And the cathode is connecting to stamping material and the anode is connecting to stationary part or leather fixing material.
4. Stamping material and leather fixing metal.
5. Transformers – 2 transformers are using for making high-frequency current.
LT Transformer – This is mainly low voltage but high current. Because of evaporation of any metal, you need a high current (20 to 70amps), to melt the evaporation material kept on the surface. It basically consists of a step-down transformer, which produces low voltage and high current at the secondary and the evaporation electrodes where tungsten filament (Valve) are connected to this output. In here out output voltage of LT transformer is 12V and it is connected to the valves of the cathode or positive side of the valve.
HT Transformer – This is mainly high voltage in (KV), DC voltage, which is useful for plasma glow cleaning and to small extend DC sputtering if the KV provided up to 4-5 KV. It basically consists of a step-up transformer, which generates the high current and then rectifier by using a Diode board which convert the stepped-up AC voltage to DC volts. In here 15KW 500 PH ceramic transformers are used for HT line. And it produces an output voltage of 2500 V in fewer amperes.
Working – When applying the switch (toggle) the two transformers are producing low and high voltage the low voltage is used for opening the valve filament and high volt is converted to DC voltage by using diode board and transferring to the stamping material. When applying the pressure to the stamping material it comes and placing near to the leather material which is placed on the metal just beneath of the stamping material. A high voltage converts to the high-frequency current and it makes heating the die plate placing on the stamping material. By applying the pressure to the die plate and comes near to the leather at a certain distance around 1mm – 3mm the +Ve and –Ve of the valves are coming to short through the air and the air comes in high heat at this area only. When a leather place between these two plates (stamping plate and leather placing plate) this hot air melt the leather and comes to the gap of the designed die plate. When releasing the pressure on the plate the leather material suddenly cool and it comes embossed finally.
Check the automation courses in Kochi that discuss about the Embossing machine