In manufacturing, multiple practices are followed to produce parts. One traditional approach is the mass production of parts to bring down the cost per unit. However, it is not feasible for prototyping projects and small businesses; here comes the role of small volume CNC machining strategy. It focuses on creating a few prototypes or a small batch of products to initiate operations or test the market.
This article highlights the advantages and applications of small batch CNC machining. It also explains the best design practices for low volume machining and how you can choose the best service provider.
What is Low Volume CNC Machining?
Low volume CNC machining is a strategic approach designed to manufacture a low to moderate quantity of items, typically ranging from 10 to 10,000 pieces, though this range can vary significantly among manufacturers. For some, low volume means producing 100 to 1,000 units, while others may consider several thousand units a low volume.
Like mass production, the objective here is to produce parts at cost-effective prices. However, the scale of production is more controlled, which provides greater flexibility, rapid turnaround, and minimal investment.
Benefits of Low Volume CNC Machining
Small batch CNC machining is popular due to its multiple advantages. Here’s a detailed list of how it benefits the product owners and manufacturers:
Cost-Effective Manufacturing for Short Runs
It’s true that cost per unit decreases in large-scale production. However, the setup cost (tooling and equipment) for that scale is thousands of dollars. When small batch production is in sight, only a few CNCs are enough to machine parts.
A significant investment is required to produce such an inventory and that’s a financial risk for small businesses. So, in the perspective of new enterprises low volume production is a cost-effective option.
High Precision and Consistency in Custom Parts
With smaller quantities, more attention can be given to each part, ensuring they meet the exact specifications. For instance, aerospace components that require precision and critical inspection are often made in low volumes.
Regarding the consistency of machined parts, since a programmed computer numerical control (CNC) system makes them, the designs are replicated with utmost precision and accuracy.
Reduced Time to Market
In low volume CNC machining, manufacturers don’t need to wait for full runs to complete. Instead, smaller batches can be produced quickly; they can test them, make changes during the test launch, and get back better. So, the use of low volume CNC machined parts allow them to quickly evolve and penetrate the market.
Manufacturing and Design Flexibility
With smaller batches, it’s easier to tweak designs between runs without significant cost implications. For example, an automotive company might test different geometries of a component in small runs to determine the best design before committing to high volume production.
Moreover, in low volume production runs, manufacturers get an opportunity to test and fine-tune the manufacturing workflow i.e. figure out the machining process and best order of operation.
Reduced Inventory Risk
Low volume is more of an on demand CNC machining approach, where production aligns closely with actual demand rather than forecasting large quantities. Instead of manufacturing thousands of units in anticipation of demand, you can produce small batches as needed.
With reduced inventory and significantly less financial risk, businesses can quickly adapt to market trends or switch designs without the burden of overstocked products.
When You Need Low Volume CNC Machining
Low volume CNC is an approach for new businesses in prototyping phases, or need small batches of custom parts. Follow are some practical use cases for making low volume CNC machining parts:
Ideal for Prototyping and Product Testing
When developing a new product, prototyping is necessary to test the functionality and design of parts. For instance, medical product researchers, may request a batch of a few surgical instruments and distribute them among the community to test them before they push it to the market.
Custom Parts for Specialized Industries
OEMs often need a batch of customized products for specific applications. For instance, an automotive manufacturer can order a limited run of custom-designed intake manifolds for a high-performance vehicle model.
For Startups and Small Businesses
If you’re a small business that targets niche audiences, you often need a limited quantity of items. You can create a small number of goods; about 50 to 100 units are enough to know the market demand and upscale things later.
Supply Chain Resilience
Supply chain resilience is the ability of a supply chain to prepare for, respond to, and recover from unexpected disruptions. With low volume production, companies can better handle and cope with sudden market disruptions, with less financial costs.
Scalability Benefit for CNC Machine Shops
If the short runs are successful in the desired performance or indicate good results from initial market testing, low volume CNC machine shops can easily scale up the production in a short time. Additionally, there will be lower tooling & overhead costs for subsequent batches.
These high-precision CNC machine shops can also produce parts in small batches to test the accuracy and consistency. It allows for optimization of the tooling and setup variables for utmost machining accuracy.
Tips for Reducing Low Volume CNC Costs
The goal of low volume CNC is largely to keep costs manageable for both businesses and manufacturers.
The following practices can help you manage your approach:
Optimize Design for Manufacturability (DFM)
To optimize design from a manufacturing perspective, the basic advice is to move with standard dimensions and geometries. For instance, avoid designing holes deeper than six times their diameter, as this complicates chip evacuation and requires expensive tooling. Avoid any non-critical features or unnecessary complexities to make the machining process simpler and more cost-efficient.
Use Standard Tools and Fixtures
Avoid the use of custom tooling and fixtures unless it is absolutely necessary. Instead, use standard tools as they are easily available and cost less. Standard tools take less time to set up and are compatible with multiple machines. For instance, you may use modular fixture systems and standard CNC cutters.
Choose Cost-Effective Materials
Material selection should always be based on the application, but cost and machinability are critical factors. Softer materials like aluminum or plastics are easier and cheaper to machine than harder materials like titanium. If you end up selecting the wrong materials, they can significantly inflate costs and make machining harder.
Limit Secondary Operations
Secondary operations, such as polishing, anodizing, or engraving, add additional time and expense to the process. Unless absolutely necessary for functionality or appearance, these steps should be minimized.
Leverage Multi-Part Machining
Multi-part machining means machining multiple components from the same setup. This technique reduces changeover times and increases efficiency. For example, if you’re producing multiple identical brackets, you should devise a strategy or mechanism that lets you cut multiple items from a single block of material.
Batch Similar Parts
While low-volume machining allows for customization, costs are best optimized when producing a batch of similar parts. Dissimilar parts require separate setups, tools, and programs, driving up individual costs.
Avoid Tight Tolerance
Tight tolerances are sometimes essential but they are costly from a manufacturing perspective. To achieve precise tolerances, you may need to lower machining speeds, require specialized tools, and frequent quality checks.
Low Volume vs. Mass Production CNC Machining
Mass production vs low volume production is a very debated topic in the industry. People are often curious about how they differ in the grand scheme of things.
Production Scale
Low volume CNC machining is intended for a small batch, probably 10 to 1,000 or maybe 10,000. Whereas, high volume CNC machining production involves the manufacturing of tens of thousands or even millions of parts.
Tooling and Setup
Large scale production requires expensive tooling, automated setups, and additional labor to handle large volumes. It also demands more inventory space to store the finished goods. In contrast, low-volume production can start with a couple of CNC machines and minimal tooling.
Lead Time
Lead time refers to the total time taken from the start of production to the delivery of the final product. Low-volume machining shortens lead times – it ranges from a few days to a couple of weeks, depending on the complexity. For mass-produced items, lead times are usually longer, spanning weeks or even months.
Cost Per Part
The initial setup time and cost for mass production is higher due to tooling and equipment, the cost per part decreases as the production volume increases. In low-volume production, the per-part cost remains higher because the cost is distributed across fewer units.
Customization Flexibility
Low-volume production allows for easier customization and micro-management of individual parts, making it ideal for specialized projects. In high volume production, customization is less feasible as it disrupts the uniformity of the process.
Other Low Volume Manufacturing Processes
Besides CNC machining, there are a couple of other popular manufacturing processes for small-batch production.
Low Volume Injection Molding
Injection molding makes parts by injecting molten material into a mold. The process is primarily popular for plastic products though metals can work too. Small batches of items like enclosures, caps, custom housings, or functional prototypes are made via injection molding.
Low Volume 3D Printing
3D printing is an additive manufacturing process that creates parts layer by layer using materials like plastic, resin, or metal. This method is best for making prototypes or complex geometries that would be challenging with traditional machining methods.
Choosing a Low Volume CNC Machining Service Provider
Before choosing a low volume CNC service provider, we would recommend keeping in view all these factors:
Quality
Quality can be assessed through multiple criteria. One way is by reviewing testimonials and case studies from their previous projects. Another is by examining the precision and tolerance levels they claim to offer. You may also request sample parts to verify whether their work meets your specifications.
Lead Time
Request the lead time from the provider and ensure it aligns with your project timeline. It’s advisable to request quotes from multiple service providers to compare their timelines and then determine which one suits your schedule.
Pricing
Request cost estimates for different batch sizes to see how pricing scales with volume. Check if the cost per unit decreases when ordering higher quantities. Compare quotes from various providers to get a clear idea of the market rates.
Certifications and Industry Standards
Ensure the provider adheres to relevant industry certifications and standards. For example, ISO 9001 ensures quality management processes, while ISO 14001 focuses on environmental management systems.
Choose RapidDirect CNC Machining Services
Looking for a CNC machining services provider? Whether it’s low volume or high volume production, you can count on RapidDirect for all your CNC machining needs.
We have a massive lineup of over 700 CNC machines (including 5-axis CNC machining equipment), plus 3D printers, molding capabilities, laser cutters, and wire EDM machines to handle any product requirements. You can choose from more than 100 materials and over 60 surface finishes to get exactly what you need.
Just send us your requirements, and we’ll get you an instant quote. Let’s make it happen!
Frequently Asked Questions
The definition of low volume varies among manufacturers. Some categorize it as 1 to 100 pieces, while others extend the range up to 1,000. Generally, any quantity under 10,000 is considered a small batch suitable for low-volume CNC machining.
The timeline depends on the quantity and complexity of the parts you need. For a single product, service providers like RapidDirect offer lead times as short as one day. On average, though, low-volume CNC jobs take a few weeks to complete.
For the choice of materials, the priority should be the desired applications and then the machinability. In regards to that, the best materials for low volume CNC machining include stainless steel, aluminum, brass, copper, acrylic, ABS, PVC, and PEEK.
With CNC machining services, especially those available at RapidDirect, you can achieve tolerances as low as 0.0001 inches.
