vacuum former

This is my first vacuum cleaner version and if you jump to the last dry word you will see why I need to make some changes.
The new version is where the vacuum front 2A vacuum molding machine is used to form the plastic sheet into a mold shape.
Vacuum molding is widely used in industrial production of various plastic products.
For this instructable, I will tell you how to make the vacuum forming machine, I hope to do more instructable for what you can make with this machine.
If you don\'t know what the vacuum cleaner is and want to know how it works, please read this before proceeding.
My machine is not like the machine on the link, but the principle is the same.
This is the basic list of most of the materials I use to assemble the machine and some of the tools I use. Material: oven1. Nichrome wire2.
Hardibacker cement board 3.
Ceramic bracket 4.
Aluminum flashes 14in. wide5. 1x3in. Wood stud6.
Various longitudinal wood screws. 8-
32 machine screws 8.
14 gauge stranded Line 9.
Screw terminal block 10crimp-On the connector. 1/4in.
Thickened plywoodControl Box1.
4 Post electric box 2.
4 600 watt dimmer switches. 4 dials (radio shack)4.
14 gauge stranded line 5. wire nuts6.
Extension cord with a bare wire ENDV acuum/platen1. 1/2x3/16in. Balsa Wood2. 1/4in. Thick Plywood3. Wood Glue4.
2x4 Wood studframe 1. 1x2 wood stud2. Two Hinges3. Two window frame locks. Two 6in.
Corner 1Jig saw2. Miter box saw3. Hack saw4. Utility knife5.
Wire cutting machine/stripper6. Mulitmeter 7.
Drill this is the prototype machine I built before building the real thing.
It uses one to heat up in a full aluminum oven.
This is an oven in the design, on the table board.
My machine will be a flip machine because the oven and the drum are at the same level and the frame is flipped between them.
Now that the oven housing is complete, it\'s time to continue making the part of the oven, heating the coil.
There are many different ways to generate heat in the world of vacuum molding machines, but the simple fact is that you only need a heat source that can effectively heat the entire plastic sheet.
I found some Nichrome wire heating elements in a remaining store, but there are many other options.
You can use the electric baking elements, the toaster oven, the stove, the hot gun, and I have even seen the gas heater used.
Nichrome wire is a kind of wire in the toaster, it works, it will heat up when the current passes through the wire.
I will talk about how I can determine the wire for the oven so that it can run from a normal home 120 V socket.
Specifically, I did this, but these same equations apply to any other oven like this as well.
The first equation that we need to study is usually called Ohm\'s law: V = IRorI = V/RorR = V/IIn this equation V = voltage, I = current, R = resistance
The unit of voltage is volts, the unit of current is amps, and the unit of resistance is ohms.
For this oven, I would like to use 120 V so I can get a part of this equation.
Now is the time to measure the resistance of the nichrome line.
This can be done with a normal multimeter, with a resistance of about 74 ohms for each of my heating elements.
The resistance of Nichrome varies depending on the diameter of the wire and the length of the wire used.
If you build your own oven with a roll of nichrome lines, you can make changes based on your own situation.
So let\'s calculate the current (I)
, From these two values: V = 120VR = 74 ohmsI = V/r I = 120/74 I = 1.
62 ASo if I connect a heating element to the wall, the current passing through it will be 1. 62 Amps.
But I want to connect 8 heating elements, not just one.
There are two ways to connect elements in series or in parallel.
Each method has its benefits, but what we care about is the resistance of the whole oven.
In this way, we treat each element as a resistor.
If I connect these elements in series, they will all be connected end-to-end, and the total resistance of the system will be the sum of the resistance of each element.
This means that the resistance is 592 ohms, so the current is: V = 120VR = 592 ohmsI = V/r I = 120/592 I = 0.
You will find that it is not enough to heat the wire to the desired temperature.
This chart is infraredheater.
Com shows some common line gauges and the number of amps required to heat them to a certain temperature in order to get more amps by connecting the wires required for the element in parallel.
This equation shows how to solve the equivalent resistance in a parallel circuit: 1/Req = 1/R1 1/R2 1/R3. . .
In this equation, Req is the equivalent resistance or total resistance of the parallel circuit, and R1, R2, R3, etc.
Resistance of each resistor.
I have eight separate resistors or heating elements in this case.
So with this equation and the equivalent resistance of the individual 74 ohms: Month/= item required for 1/74 months/74 req = action to be taken.
The current of the 25 ohmsSo parallel circuit is: V = 120VR = 9.
25 ohmsI = V/r I = 120/9. 25 I=12.
Now, it\'s more like the number of amps we need to heat the coil.
I can connect the oven in parallel and call it a day, but I want to have more control over the temperature and current.
For this I decided to use the normal lighting dimmer switch.
The dimmer switch is basically a variable resistor, also known as a potentiometer.
By changing the resistance of the circuit, I can control the number of amps flowing through the circuit to control the temperature.
I bought the dimmer switch from Home Depot with a rated power of 600 watts.
Watt is the unit of power, so I need some way to connect it to the voltage, the number of amps, and the resistance.
This equation does this: P = VIorP = (I*I)RorP=(V*V)
/RTo find current: P = 600 WV = 120 VP = VI 600 = 120 * I = 5a so one of the dimmer switches can handle up to 5 amps at 120 V
The current previously calculated for the parallel circuit is 12.
9 amps, this is big for a dimmer switch.
So I decided to control two heating elements with four dimmers, each one.
You can see in pdf how it is connected.
If you don\'t understand these things because here is a calculator that can do it for you, but it works differently than the way I calculate the oven.
It will ask for your final oven request and then tell you what you need.
I started with what I had and came up with a way to make it work.
I think most people do this.
The calculator also assumes that you are building a specially made oven with spiral Nish Roman wires.
If you decide to go this way, there is a link here that can really help you find the supplies, which is the way I wired the oven.
Here are some details of how I actually build it.
I used an electric box for 4 people to fix the dimmer switch and an extension cable with the female end of the cable cut off to insert into the wall.
I used 14 gauge stranded wires throughout the electrical system.
Four wires and a ground wire extend from the box to the oven and connect to the oven with a screw terminal.
From there, the wires are divided into four groups of each of the heating elements.
Then they connect to 8-
32 machine screws that also hold the heating element in place.
Inside the oven, the short part of the non-insulated wire is attached to the heating element holder and then used about 4-
40 machine screws
In order to make the electrical connection easier to complete, the number of wires running in the oven is minimal, aluminum flash is used as a conductor.
Pieces cut in such a way that allow electricity to come in four different places and then have a common basis for the entire system.
The four small pieces on both sides are the power connection, and the large pieces in the middle are the ground.
This idea lacks traces on the PCB and is based on this idea.
You might ask, why are you using aluminum?
The heating element emits infrared rays that are basically hot.
Infrared reflection from the aluminum sheet onto the plastic sheet.
This type of heating is known for radiation.
You may have heard of the convection oven, which is basically the same setting, but added a fan to move the air inside the oven.
This moving hot air helps to heat items in the oven faster.
I\'m thinking about adding a fan to the oven later to see if I can get better results.
The template is the surface where the mold is placed and the plastic forms a vacuum seal on it.
There are many different template designs, but most of them have many small holes and the air is pulled through to create a vacuum.
This is how my platform is designed.
I used two sheets of 1/4 in paper to make the template.
Plywood cut into 23 in. long and 11in. wide.
At the bottom I cut about 1 In.
There is a hole in the middle so I can put the PVC fitting in.
PVC parts are selected so I can connect the Shopvac to the template and of course this will create a vacuum.
I drilled a bunch of 11/64 at the top.
Holes in the pattern.
The pattern and size of the hole is up to you, just be reasonable.
The two pieces are separated by balsa wooden strips.
Balsa wood is 1/2x3/16 in.
And cut to fit the perimeter of the top and bottom template parts.
Then the whole thing sticks together.
The idea here is to keep the volume inside the platform board as small as possible.
This way, when you flip over the shopvac, you don\'t have to pull a bunch of air out of the template, and then pull it out from under the plastic.
The purpose of the frame is to keep the plastic sheet in the process of heating and forming the plastic sheet.
I made this frame with 1x2 in. wood.
The interior size of the frame needs to be the same as the template and oven, so my size is 11x23.
To clamp the plastic, I used the belt lock that you can get from Home Depot, and the hinges make sheets that are easy to change.
When building the frame and the whole machine for this, you need to consider the size of the plastic sheet you want to use.
In my case, I want to use 12x24in.
So the frame, oven and table Board need to be a little smaller.
I choose 1/2in.
That\'s why everything is 11x23 in.
This size also determines how large objects you can form.
You also need to consider your plastic supplier.
Where do you get the sheets, how big size sheets can you get.
I know you can get 4 x 8ft.
But I believe the standard size in many places is 72 x40in.
You don\'t want to waste part of the paper because your previous size doesn\'t match the paper.
As far as the plastic supplier is concerned, the signboard store may be a good local source.
You can try it online or use it on my machine.
Screw the plywood around with 1x2 to add support.
In the first trial run of my machine, the oven was just sitting on the base with the spacers and the platform plate was fixed in place with adhesive tape.
I made the angle brackets but can get similar angle brackets from any hardware store.
The oven and roller align with the frame when they flip on both sides.
For my template, there is no seal around the edge because when the hot plastic is forced below the top edge of the template, it forms a seal.
Now is the time to test.
I got one. 020in.
Thick polystyrene in a hobby shop.
This is a bit thin for vacuum forming, but it depends on what you are doing.
The normal thickness is between the two. 040 and . 080.
Finer materials can be formed, but close attention is required when heating.
This is the problem I encountered when I first tested it.
I turn on the oven and let it warm up for a while.
When the oven was heating, I cut another piece of hardibacker as the lid for the oven.
Then I put the plastic on the shelf, on the oven, and put the lid on it.
When the plastic starts to heat, it starts to bend and then starts to sag.
Usually, you can determine when the plastic is formed by the amount of dents in the plastic.
But this kind of learning has to come from experience and your first few times may not be very good.
Due to my lack of experience in using the machine for the first time, the plastic is heated much faster than I thought, falling to a very low level, touching the coil and catching fire.
As you can see from the photo, it melts in the oven.
This ruined the oven, but I can be cleaned and used again.
I don\'t have time to do it, though.
I live in a home away from home in the summer and can\'t work for months.
So at least now I \'ve learned a lot about how the vacuum molding machine works and how to put it together.
I might try to replace some of the parts of the machine to make it stronger and heat the plastic more evenly.
If I can tell you one thing, it is to make a vacuum molding machine here and prepare the fire extinguisher when you have it several times before the test.