Low volume manufacturing methods: The ultimate guide

As the world is growing fast, the demand for new products with the latest designs is also increasing. So, big companies and beginners first need to manufacture, test, and market their products in the real world on a small scale.

That’s where low volume manufacturing of products comes for low-risk investments.

The benefits of low volume manufacturing of new products are given below;

• Field test of products on a small scale is less risky
• Low volume prototype manufacturing is budget-friendly
• Affordable and efficient machinery up to 50,000 pieces/ year
• Less preparing time for new products and quick investment returns
• Excellent quality finished products as compare to huge volume manufacturing machines

This means you can develop and test your prototypes at low prices and even introduce them in the market on a small scale of up to 50,000 pieces/year to check public response. But the question still exists, how can we achieve low volume manufacturing of new products? And who is going to provide you with all such customized machines for your unique project? 

There are three methods used for low volume manufacturing of products;

• 3D printing
• Vacuum casting
• Injection molding

Each of these methods has its own applications, pros, and cons.

Let us learn which method you are gonna need according to your needs;

1) 3D printing

What is 3D printing? How is it beneficial in low volume manufacturing of products? What are the limitations of 3D printing?

Well, 3D printing is one of the most fast-growing methods in making real-life 3D models. 3D printers are machines that make a 3D model from a software file by laying down many thin layers of material in series.

There are basically 3 kinds of 3D printers;

• Regular 3D printer
• SLS 3D printer
• SLA 3D printer

SLS and SLA 3D printers are mostly for low volume manufacturing of complex structure products with an excellent surface finish. You can even use these printed products as prototypes and test them in the real world.

Pros of 3D printing

3D printers have many pros which are given below;

• Best for prototypes
• Easy to make products
• Excellent surface finish
• Different materials can be used
• Even complex structure products are efficiently made
• Use different color materials for different color final products
• No changing of parts is required for different products designs
• Can be used to make master models for the vacuum casting method

Cons of 3D printing

• Requires a lot of time to 3D print a model
• Material to manufacture products is costly
• On average, only 1 medium-size product can be made per day

2) Vacuum casting

Vacuum casting is also a very famous method in which silicon molds are used to cast resin prototype products.

Why do we need vacuum casting if we already have efficient 3D printers?

3D printers are good, but they are not as efficient as vacuum molding. Final product quality can be the same, but with vacuum casting, you can make up to 5 prototypes per day, but with a 3D printer, you can only make 1 or 2 prototypes per day. With vacuum casting, you can get a prototype quality near to the final product.

You can use an SLS or SLA 3D printer to make a premium quality master model for the vacuum casting process.

Pros of vacuum casting

Vacuum casting has the following advantages over other low volume manufacturing methods;

• Suitable for more real prototypes
• Overall, cheaper than 3D printed prototypes
• Only 1 to 6 hours for curing, faster than 3D printers
• Each mold can be used to make up to 50 prototypes
• Provide more excellent surface finish than 3D printers
• Provide a low-cost variety of color range for prototypes
• Even opaque prototypes can be made by vacuum casting 
• Suitable for small scale business, up to 5 pieces per day from one mold
• Vacuum cast prototypes are mostly used for marketing due to their premium quality
• Vacuum cast prototypes give more accurate results in field testing than 3D printed prototypes
• Different resin materials provide more hardness, surface finish, and temperature variety for prototypes

Cons of vacuum casting

There are few cons of vacuum casting:

• Requires a lot of experienced labor
• Molds can only last for 30 to 50 times
• In post-processing of surface, inner areas are not reachable
• Sometimes, you will get rounded edges instead of sharp corners
• Slower than injection molding, only 5 pieces can be made per day from one mold
• Requires a 3D master model to make a mold, which is mostly made by an SLS & SLA 3D printer

3) Injection molding

Injection molding is the third level for low volume manufacturing of products.  When you are done designing and testing prototypes with a 3D printer and vacuum casting methods, now it is time for the launching of the product on a small scale. In this method, heated material is injected into a mold and the cooldown product is kicked out in a few seconds. It is definitely the most common method in plastic parts manufacturing.

The injection molding method mostly use two kinds of molds;

• Aluminum molds, lasts up to 5,000 molding cycles
• Steel molds, lasts up to 100,000 molding cycles

Pros of injection molding

• Affordable
• Production cost is much cheaper 
• Adjustable molds for new products
• Low-risk investment with quick returns
• Ideal for small businesses with a demand of 1234 pieces/day
• Suitable for small and big companies alike to check their products response in the market
• The supreme quality of the products is as same as costly, huge volume manufacturing machines
• Requires only maximum of 70 seconds to make a final product, while 3D printing requires a day for 1 product, and vacuum casting can produce 5 products from a single mold in one day

Cons of injection molding

• Not suitable for initial prototype designs testing
• New molds for different products are costly and took weeks to months to make
• Not profitable for business with manufacturing demand of more than 50,000 pieces/ year

Summary

3D printing, vacuum casting, and injection molding each of these have their own roles in low volume manufacturing of new products.

You can say 3D printing and vacuum casting methods are used to develop and test prototypes in the real world. Vacuum casting is also used to run a business of up to 100 pieces per day. In contrast, low volume injection molding is used to run a medium-scale business of up to 50,000 pieces/ year. With these methods you can also check how well your new product is doing, you can plan the future of the product accordingly.

Low volume manufacturing methods give you these advantages when you design a prototype and launch a new product;

• Save a lot of your investments
• Provide quick investment returns 
• Check the public response to new product
• In case of product failure, provide a backbone
• Same premium quality as other huge, costly manufacturing machines

There are many on-demand companies such as RapidDirect, e.t.c, which provide instant quotes according to your CAD/Step file and get your design from prototyping to manufacturing one-stop service to make your business a reality. 

You can see the chart below to differentiate above three low volume manufacturing methods;

	3D printing	Vacuum casting	Injection molding
Usage	Prototype designs testing	Prototype designs testing	Run a small business Check public response of new product
Molds kind	No molds needed	Silicon molds mostly	Aluminium molds Steel molds Others
Piece per day	1 maximum	5 maximum from 1 mold	1234 per day
Quality	Excellent	More excellent	Premium
Product production cost	High	High	Cheap
Durability	3D printer can last for years with no replacements	Silicon molds needs to replace after 30 to 50 molding cycles	Aluminium molds 5,000 molding cycles Steel molds 100,000 molding cycles
Cost of mold replacement	No molds	Medium	Very High
Ease to use	Hard	Hard	Easy
Surface finish	Good	More than 3D printers	Premium