In many product designs, parts begin life machined from aluminum billet. Billet machining is a great way to prototype a part quickly, validate designs and get early products to market. However, as the product evolves and order volumes increase, continuing to machine parts from billet can become unnecessarily expensive and inefficient.

This is when aluminum casting – especially aluminum sand castings become attractive, especially when combined with final machining.

These factors help assist with cost, lead time, and design flexibility.

At Cast Metals Technology, we help customers transition from billet-machined parts to near-net-shape aluminum castings with final CNC machining. Below are key factors that show why it may be a good time to make the transition from aluminum billet to aluminum casting.

When Is It Best to Move from Billet to Aluminum Casting?

1. High Material Waste from Machining

If your current process starts with a large block of aluminum and removes 60–90% of the material, you are paying for aluminum that turns into chips.

Example:
A housing machined from a 40 lb. billet may result in a finished part weighing only 10 lbs. That means you paid for 30 lbs. of material that never becomes part of the product.

With aluminum casting, the part is cast close to final shape, significantly reducing material the amount of material utilized and reducing the overall CNC machining time.

2. Increasing Production Volumes

Billet machining works well for:

  • Prototypes
  • Low-volume production
  • Fast design changes

As volumes rise into the hundreds or thousands of parts per year, cycle time, machine time and tool wear become major cost drivers.

Casting allows you to:

  • Produce near-net-shape parts in higher quantities
  • Reduce CNC cycle time significantly

This makes aluminum sand casting an ideal next step for low to medium production volumes where permanent tooling costs of die casting are not justified.

3. Complex Geometry or Thick Sections

Billet machining is limited by tool access and cutter reach. Deep pockets, internal cavities, thick ribs, and complex shapes can drive up machining time or make certain features impossible.

With sand casting, you can:

  • Integrate ribs, bosses and mounting features
  • Form internal cavities and hollow areas with cores
  • Design parts for strength without excess material

Example:
Pump housings, gearboxes, valve bodies, and structural brackets are often excellent candidates for casting because of their geometry and wall thickness requirements.

Advantages of Aluminum Sand Casting + Final Machining

Significant Cost Reduction

Cost savings typically come from three areas:

  1. Lower Material Cost
    You only cast what you need instead of machining away excess material
  2. Reduced Machining Time
    Final machining focuses only on critical dimensions and certain surfaces, not machining and shaping the entire part.
  3. Lower Tool Wear and Machine Usage
    Less cutting time and less machine time equate to longer tool life.

In many cases and depending on geometry and volume, many customers see a 20–50% cost reduction per part after converting from aluminum billet to aluminum casting.

Improved Design Freedom

Castings allow for features that are either difficult or very expensive to machine, including:

  • Thicker structural sections
  • Curved profiles
  • Integrated mounting points
  • Weight-reducing pockets formed in the mold

This often leads to stronger parts with better performance, not just lower cost.

Excellent Quality with Proper Process Control

Modern aluminum sand casting is far from the rough, inconsistent process many people imagine.

At Cast Metals Technology, we focus on Quality with:

  • Controlled melt practices
  • Proper gating and riser design
  • Consistent molding methods
  • Full CNC machining on critical surfaces

This Quality Focus results in:

  • Reliable mechanical properties
  • Dimensional stability
  • Excellent surface finish after machining

Faster Lead Times Compared to Complex Machining

When machining from billet:

  • Each part has a CNC machine set up time
  • Occupies a machine for long periods of time
  • Allows for  potential bottlenecks to increase as volumes rise

With casting:

  • Multiple parts can be poured per mold at one time
  • Machining setup and number of machining operations is reduced
  • Machining is faster and more efficient
  • Production scheduling becomes more flexible

Once tooling is complete, customers often see shorter overall production lead times compared to billet machining at scale.

Real-World Example: From Billet to Casting

A customer originally machined a structural aluminum bracket from billet for a specialty vehicle application.

Challenges:

  • Long CNC machining cycle times
  • Rising costs as demand increased

Solution:
The part was redesigned for aluminum sand casting, integrating ribs and mounting bosses directly into the casting. Final machining was applied only to necessary surfaces and bolt hole locations.

Results:

  • Significant reduction in CNC machining time
  • Improved structural rigidity due to added cast-in features
  • Significant cost reduction per part

Is Aluminum Casting Right for Your Part?

Aluminum sand casting is an excellent fit when:

  • A part has moderate to complex geometry
  • There is a need to machine away large amounts of material
  • Volumes are growing and CNC machine time is critical
  • Strength and durability are critical

Billet machining still has its place for:

  • Prototypes
  • Very low-volume specialty parts
  • Tight tolerances across all surfaces

The key is knowing when to transition from billet to casting and designing the part properly for casting to maximize the benefits. This is where Cast Metals Technology can help customers weigh the costs and advantages of converting from billet to aluminum castings.

Partner with Cast Metals Technology

At Cast Metals Technology, we don’t just pour metal – we work with our customers to evaluate designs, recommend casting-friendly improvements and deliver fully machined, ready-to-install, quality aluminum parts.

If you’re currently machining parts from billet and wondering if aluminum casting could reduce your costs and improve performance, our engineering and production teams are ready to help evaluate your project.

Contact Cast Metals Technology to explore whether converting from billet to casting is the right move for your next production run.

PHONE: 765-584-6501 | info@cm-tec.com