Thermoforming and working with material guage/thickness have many variables. The slightest deviation can have major cost ramifications when produced, especially the larger the production runs.
There is just thermoforming (actual bending and manipulating of raw material around simple mold), rotational molding( as it sounds material in and then spun into cavity walls ),vacuum forming (air pressure pulls material into wall cavity to mold), injection molding (as it sounds, injected material into cavity), and blow molding( literally inject tiny particulate and then blow air into material and form to cavity). Each application's tooling varies in cost in relation to the type of thermoforming, material, and quantity.
Mold design made with the right material. A quality mold is the most important factor. Heat/cool times are key.
What mold design will be best suited to produce given part?
What material will work best? Cost sensitivity in relation to material?
What are design requirements of finished part?
Will thermoforming require plugs (help pre-stretch raw material sheet and assist in forming, conform to cavity) and/or ring assists(help prevent webbing in multi cavity tool)?
wood molds- usually just low- low- low output and more so for sampling/prototyping before moving to actual production tooling mold
Plaster molds-don't even consider
Plastic molds-for more rapid forming cycles, using phenolic or epoxy resins. Do not conduct heat well so can't do rapid cooling- usually not used much/at all anymore
Aluminum- most common, casted, conducts heat well and cools quick allowing faster cycle time-- these are prevalent and more than likely what would be used for production
Mold design involves: Radii, draft angles, undercuts, and vacuum holes.
Tooling- can be very, very expensive, is a capital expenditure, determining the right quantity of cavities (greater output with more cavities and reduced trim scrap) (in relation to output production from machine time) and machinery used, also in relation to materials you decide to use.
What usually happens is you will have the manufacturer decide the best outlay of the mold, but, be aware of what you are doing and what your future is going to look like. We have made molds to produce an item, and they have ranged from a few thousand up to 150,000. What happens if your product takes off? You might have a 2 up, 4 up , or even 8 up die made initially, and it does well to meet demand. However, you were only producing say 20,000 units 2 times a year. Now, you need 100,000 to meet demand per run. The original tooling now requires more machine time from the manufacturer, and thus, your unit price will suffer. Sometimes you have to accept it, but, at what point does real money come into play? You might not reduce your unit cost with greater volume. You will be forced to evaluate your numbers and if it does well you will more than not have to produce another new tool/die at some point. As stated above, tooling can be a bear that absorbs so much time, effort, and money that you need to learn and become cognizant of actual costs to you.
Materials:
PET or PETE- polyethylene terephthalate
HDPE - high density polyethylene
LDPE- low density polythylene
PP- polypropylene
PVC- polyvinyl chloride
Start looking at all products made of plastic. Whether bottles, cookie trays, clamshells, bottle caps and then look up how they are made. It is an easy way to become familiar with materials and there common uses.
Machine time and scheduling- your enemy as a customer to any manufacturer. You have to understand the time and effort it takes for companies to look at projects. You are competing with current customers and needs and the time allowed for you to make your product on their time. They are driven by machine time and the cost analysis of profit into time.
Take no offense here with this, I don't know if you'll have a company or just approaching as an individual, but, be prepared to show you can pay for what you are looking at before some people will even talk to you. You will run into many people who will not even give you the time.
If you need anything I'll try and provide what help I can with anything you might have.
