Posted on: July 19, 2018, | By Mandy, WayKen Project Manager
The world of product designs continues to experience innovative and revolutionary changes after regular time. Lifetime of products are getting shorter and so as expected in market. As a result, product manufacturers are moving away from mass production and changing their standards to low volume production.
1.What is low volume production?
Low volume production or low volume manufacturing is different for different persons in manufacturing context. However, it usually means that the production of less than 10,000 parts or products per month. This is not exact figure, it can vary depending on different factors like size, geometry of part and different other factors.
2.Benefits of Low Volume Production
Thinking of low production volume and manufacturing might give a sense that it is low profit that can’t give you enough profit as a mass production manufacturing can give. However it is opposite to it, producing less can benefit your business. As now market is growing towards new trends which demands low production volume. So, we have discussed below few benefits that can give you profit.
2.1.Saves your money
Low volume production usually means production of parts usually between 500 and 10000 and company of any size can make money with this range in small setup. Low volume manufacturing is flexible because it allows you to quickly change your design or product size without altering the total number of products and without any loss. So companies can easily make money with this. If during the process, something goes off the line then you can easily made it again without any difficulty. 3D printing is best process to create customized design to give flexible designs.
2.2. Save your budget so that improve cash flow
Low volume production can save your money in different ways. It is right that manufacturing cost goes down when the number of production parts goes. What could be in case of low production part? In mass production you obviously need to make expensive tools especially die casting and need to be hardened and passed through heat treatment so don’t worn out throughout the process but in low volume production when you probably need 100k products then you don’t spend much on making tools because they have to work for short time. So, when a factory is set up for mass production they ask you to place minimum order or they have some minimum limit because they have much inventory in raw material. But a small set up of low production doesn’t need any minimum order and can work on your customized order efficiently and economically.
2.3.Give fast market
As we know that day by day new innovations are coming and to cope with market industries have to change their standards. Low volume production is a great challenge to fast growing market and it can easily meet client changing and low volume demand. So, it helps you in making your products sellable without just storing in inventory.
2.4. Helps growing small start-up
In mass production you need to have big product line and product supply chain and needs bigger investment but if you have small investment then you can also grow your business locally by making your products according to customers’ requirements.
2.5. Shorten production time
For mass production, the production time of molds generally takes at least one month, then comes to low volume manufacturing it takes less time as compared to mass production. While by using vacuum casting, 3D printing and reaction injection molding technologies for low volume production can greatly shorten the production time to make a fast delivery.
3.Manufacturing Process for Low Volume Production
Low volume production generally refers to small batch production with customization or high-mix. Mostly 3D printing, vacuum casting, and reaction injection molding technologies are widely used for this purpose. These all above mentioned techniques are very fast, efficient and economical. Let’s discuss each in detail.
3D printing is continuously evolving as most efficient and rapid prototyping tool for low volume production. 3D printers are becoming now popular for both industrialists and domestic purposes as it is very convenient to use and very innovative. One advantage it has that it occupies very less space as compared to conventional machines like lathe and milling machine. In 3D printing you can easily get your 3D printed design within few minutes and what 3D printer needs is that computer aided diagram for making prototype.
3.1.1. 3D printing or prototyping
- It doesn’t require injection molding and saves your budget.
- Parts can be easily prototyped in front of client so as to give better communication and short lead time.
- Provide you a facility to design, test and validate new design in less time.
- Produce lighter and stronger parts.
- Complex and free from designs.
3.2 CNC machining
CNC machining is usually used for 1-10 off prototype, especially for metal parts in low volume manufacturing. The advantages: fast lead time, low cost, accurate, stable quality etc. CNC machining gives production of parts with complexity in short time and also reducing the cost.
3.2.1.Benefits of CNC machining:
- Wide selection of materials
- Quick removal of large amounts of metal materials
- Highly accurate and repeatable
- Suitable for many different kinds of substrates
- Scalable volumes from 1 to 100,000
- Low investment in tooling and preparation costs
- Fast turnaround
3.3.Reaction injection molding
Reaction Injection Molding (RIM), also known as low pressure or high pressure perfusion. It is a new technology applicable to the production of rapid molded products. It mixes two-component polyurethane materials, and then injects them into a RTV mold under normal temperature and low pressure environment, forms products through chemical and physical processes such as polymerization, cross-linking and curing of materials. It has advantages of high efficiency, short production time, simple process and low cost. It is suitable for low volume production in the product development phase, as well as production of low volume, simpler structure covers and large-scale thick-walled and uneven-walled products.
3.3.1.Benefits of RIM:
- The product molding time is short, generally 20-90 minutes. Large-size work pieces are more stable and can control the accuracy of ±0.20mm/100mm.
- High strength, high elongation material characteristics, and strong weather resistance, can increase the mechanical properties and impact resistance by adding fillers and glass fiber composite materials.
- It can produce hard, semi-rigid and soft self-skinning foams, providing ultra-light weight, safety, comfort, energy saving and environmental protection materials for humanized products such as medical devices and automotive interior parts.
- Applicable to large-scale covers with simple structure. The product does not require uniform material thickness. It can satisfy free design and curved surface shape with different wall thickness from 3 to 20 mm.
3.4. Vacuum casting
Vacuum Casting refers to preheat, defoam, stir and cast castable materials by the original models under vacuum condition. Besides, processed by making secondary curing molding in a thermotank with temperature from 60 °C to 80 °C for several hours, to create a silicone mold. After that putting materials such as PU, similar POM, or ABS to casting under vacuum in the mold to clone the same copy as the original master. Silicone mold is popular with rapid molding process. With good toughness, vacuum casting can produce plastic parts with complex shape structure, fine surface features, dimensional stability, and material properties. It is suitable for low volume production that meets certain functional requirements during product development.
3.4.1. Benefits of Vacuum casting:
- Shorter production time from processing prototypes, turning silicone mold to casting products. Entire cycle only takes a few days.
- Stable dimensional accuracy. Room temperature vulcanized silicone rubber has excellent simulation, chemical stability and extremely low shrinkage, which can reproduce the fine features of the master parts and ensure the dimensional accuracy. Standard copying accuracy can be controlled within ±0.15mm/100mm, with the highest precision reaching ±0.05mm.
- It takes less time to make molds as compared to injection molding and 3D printing.
- Trial production of complex process structures parts. The silicone mold of vacuum casting can be easily remolded without the need to design draft angle, complex structure can be directly out of the mold, and easy for secondary casting, metal insert, investment casting, castable coloring etc.
3.5. Rapid tooling
Plastic injection molding is a common method for producing large amounts plastic parts for consumer and engineering use. The process consists of injecting molten resin into the cavity of a metal die under very high pressure. This is then cooled down, which results in the creation of a hard shape. The process usually takes few seconds to minutes depending on the part structure and size.
Rapid tooling is a bridge tool between rapid prototyping and production tool. If the demand of the product is not huge, or you want to compress the new product introduction cycle, rapid tooling should be a perfect solution for you.
The initial investment in a metal tool is relatively higher, even for a rapid tooling. By using soft steel, the simplified tooling design will save you a lot of cost and time. Almost any thermoplastic can be used; therefore, there is no any surprise if you need mass production thereafter. A production tool takes at least 5-8 weeks to complete, but rapid tooling takes only in 15 days, and you can get thousands parts within a week.
3.5.1.Benefits of rapid tooling:
- Free in choosing any plastics and resins for any application.
- Cost-effective for large volumes manufacturing.
- Mold frame sharing technology.
- Able to tool for millions of cycles.
- Stable and controllable in process.
In shorts, CNC machining might be the only solution for metal parts. If you only need dozens plastic parts and accept polyurethane as the compromised material, urethane casting is a very suitable method. If you are ready to go to the market, but not yet sure about the volume, rapid tooling might be a better option.
4. Strategies to Effectively Accomplish Low Volume Production
Following are the steps that can be used to carry out low volume production effectively.
4.1. Planning product design
From product designing to product finishing every step in product life cycle is important. Nothing can be possible without continuous flow of data. The good plan and successful completion of product design involves all process to be done good
4.2.Completing synchronized design
When we think of making product from its design to final product and bringing it in market seems easy but actually it is not as it feels. Whole processes involves in production can slow down the process. So, if you want to beat your competitors then you have to bring all the disciplines parallel to get successful and meet demands of impatient customers.
4.3.Connecting right team with right skill
Same like connecting data and processes, connecting right people for right process is also very important in low volume production. Getting diverse teams in process give rise to new ideas, perspectives and innovation and ultimately increasing profitability.
4.4.Using new and innovative technology
The world is day by day flourishing in new technologies and innovations like direct digital manufacturing (DDM), rapid tooling are few of them that have revolutionized the manufacturing processes. Using these tools you can easily carry out low volume production profitably and grow your business.
Last but not the least, supply chain is very important in the whole process. If supply chain breaks down, no matter how good you have done in data, designing and production, all your effort will go in waste. It doesn’t matter how good your idea was, if you can’t deliver the product. So, it very important to have right and flexible tools to carry out effective production that can give you money in the end.
5. WayKen's Low Volume Production Case Analysises
As experienced manufacturer in this industry, Wayken has provided low volume production service for worldwide customers from different industries like automotive, aerospace, FMCG and Defence etc.
Here is a low volume production case we produced for a customer in the automotive industry. We received a customer's request to make 6 sets of two auto parts. After in-depth communication and confirm product details and requirements, we started to carry out production of the project:
Step 1: Our engineers conducted 3D data analysis, patched entities, identified the best disassembly solutions for prototyping.
Step 2: Programming, the programmer performs the process path parameter design, physical cutting simulation verification.
Step 3: Material Selection, we choose the most economical ABS for prototype production.
Step 4: Prototype CNC Machining.
We started processing from the B-side of the workpiece, taking a total of 8.5 hours from the milling plane to the finishing machine, and then filling the gypsum turning face-up to start the processing of the A-plane. Processing the A-plane takes a total of 6 hours. After the processing of A-side and B-side was completed, our manual masters began to go to the frame and plaster to disassemble the pieces. The prototype began to appear. We polished the ash, and the prototype was completed.
Step 5: Prepare to make a silicone mold. Paste-type adhesive tape - Dividing line - Support - Fixed vent - Molded frame - Fixed prototype
Step 6: Silicone Molding, Silicone Metering - Stirring - Injection Molding - Vacuuming - Baking – Curing
Step 7: Open the mold, remove the prototype and cut the block
Step 8: Wrapping paper and closing the mold - setting the pouring port - pouring material ratio
Step 9: Vacuum Casting - Oven Curing - Mold Opening - Workpiece Take - Secondary Curing if Necessary
Step 10: Post-processing, manual repair - Bottom ash - Grinding - Spray primer - Spray paint - Baking - Finished products