Introduction to CNC Machines and Their Costs(what are torsion snap joints Bruno)

  • Time:
  • Click:5
CNC (Computer Numerical Control) machining is a manufacturing process that uses pre-programmed computer software to control machine tools. CNC machines can automate many manufacturing processes that were previously done manually. This results in higher precision, productivity, efficiency and consistency compared to manual machining.
When considering adding CNC capabilities to your manufacturing operation, one of the most important factors to consider is the cost. There are several variables that impact the overall price of a CNC machine, so it's important to understand these costs before making a purchasing decision. In this article, we'll provide an overview of CNC machines and factors that contribute to their cost.
What is CNC Machining?
CNC machining is a subtractive manufacturing process where pre-programmed computer software dictates the movement of factory tools and machinery. The process starts with a solid block of material, usually metal or plastic, called the workpiece. The CNC machine then uses tools like drills, lathes, and mills to selectively remove material from the workpiece to produce the desired part geometry.
Common CNC machining processes include:
- Milling: Rotating cutting tools remove material to produce a flat surface. Common for intricate 3D shapes.
- Turning: A rotating workpiece is precision cut with a non-moving tool to create cylindrical forms.
- Drilling: Rotating drills create perpendicular holes in the workpiece.
- Boring: An internal cutting tool creates holes by expanding the diameter of an existing hole.
The movements of the cutting tools are controlled by pre-programmed CNC machine code, which is developed from CAD models and CAM software. This automation provides consistent, high-accuracy results supervised by computer software instead of human machine operators.
Benefits of CNC Machining
There are several important benefits that make CNC machining popular across many manufacturing industries:
- Precision and Accuracy: CNC machines provide extremely consistent, repeatable results within tight tolerances of 0.001" or 0.002". This leads to high precision parts.
- Low Labor Costs: CNC automation reduces the labor costs associated with manual machining. One CNC machine can replace several manual machinists.
- Fast Production: CNC automation allows faster cycle times compared to manual machining. By reducing setup/changeover times, more parts can be produced per hour.
- Complex Geometries: The programmable nature of CNC machining allows the production of complex 3D shapes that would be infeasible with manual methods.
- Reduced Waste: CNC precision results in lower scrap rates and material waste.
- Flexible Scaling: CNC machines can be left running 24/7 with minimal supervision. Production volumes can be easily scaled by adding more machines.
While the benefits are substantial, so are the costs associated with adopting CNC machining.
Factors That Determine CNC Machine Costs
There are several variables that influence the purchase price when investing in a CNC machine:
- Machine Size: The larger the machine’s work envelope, the more expensive the machine. Larger machines are capable of producing larger parts.
- Number of Axes: More machine axes (3-axis, 5-axis, etc) allow more complex geometries but also increase costs.
- Precision Rating: Higher precision rating means the machine can hold tighter tolerances. This improves accuracy but also raises costs.
- Power and Torque: Machines with higher cutting power and spindle torque can remove material faster. This increases throughput but also price.
- Additional Features: Additional capabilities like automated tool changers, pallet changers and probing add functionality but also cost.
- Brand Name: Well-known CNC brands like Haas, Mazak, Okuma and DMG MORI command higher prices due to their reputation and track record.
- New vs. Used: Buying a used CNC machine lowers the purchase price substantially compared to brand new. However, used machine condition must be carefully evaluated.
- Location: Costs are usually lower when sourcing locally vs importing machines overseas. However, options may be more limited.
Keeping these factors in mind, here are some typical price ranges for common CNC machines:
CNC Machine Type Typical New Cost Range
- CNC Mills (3-axis): $75,000 - $150,000
- CNC Lathes: $80,000 - $250,000
- 5-Axis CNC Mills: $100,000 - $500,000+
- CNC Machining Centers: $150,000 - $1,000,000+
Buying Used CNC Machines to Reduce Costs
For small machine shops and businesses getting started with CNC, buying a used machine is a practical way to get started with less upfront capital investment. Here are some tips when assessing used CNC machines:
- Thoroughly inspect machine condition - Check for damage, corrosion, fluid leaks, etc. that may need repair.
- Review maintenance logs to confirm preventative maintenance was performed.
- Perform test cuts to verify accuracy capability. Compare measured tolerances to machine specs.
- Check hours logged on machine as higher use equates to more wear. Target <10,000 hours for mills, <20,000 for lathes.
- Consult with a reputable machinery dealer for fair market valuations.
- Negotiate warranties on critical components like the spindle, servo motors, and CNC controller.
- Budget for potential accessories like tooling, workholding, and CAD/CAM software.
With diligent inspection and negotiation, used CNC machines can be purchased for 50-80% lower cost than new. This represents huge potential savings for starting or expanding a machining business.
Operating Cost Considerations
While the purchase price is a major part of the equation, there are also ongoing operating costs to factor in for a CNC machine:
- Machine Maintenance: Yearly maintenance and preventative service is crucial to maximize uptime and lifespan. Budget approximately 8-10% of purchase price per year.
- Cutting Tools: Carbide and specialty cutting tools will need regular replacement as they wear over time. This varies by application.
- Tool Holders: Standard tool holders start around $10-25 each but special styles run $100+. A machine may need 40+ tools.
- Fixturing: Custom jigs and fixtures to hold parts add cost but are vital for job shop work. Expect to budget thousands for an initial set.
- Software: Upgrades for CAM programs and machine software licenses average $2,000-$5,000 per year.
- Operator Training: While CNC machines run themselves, trained operators are ideal. Training or job shop rates factor into costs.
- Shop Utilities: CNC machines consume more electric power. Also budget for chiller systems for water or oil cooling.
- Installation: Rigging, electrical, compressed air and other setup costs for machine delivery.
While purchase price is critical, companies should analyze expected 3-5 year operating costs to make truly informed CNC machine investments.
Optimizing CNC Machine Investment Value
Here are some tips to maximize value and minimize total costs when investing in CNC equipment:
- Purchase machines with growth in mind. Overcapacity is preferred to lack of capacity.
- Seek out factory rebates/discounts offered by dealers and manufacturers.
- Consider leasing options to minimize large upfront payments for those credit qualified.
- Standardize on popular controller models like Fanuc or Siemens to simplify training and programming.
- Opt for sufficient power, precision, and axes to minimize need for upgrades later.
- Focus on high-dollar equipment components with longest lifespan like the machine structure, spindles, ballscrews. Other items can be replaced cost-effectively.
- Utilize available tax incentives for capital investments like section 179 deductions and bonus depreciation.
With proper planning and smart purchasing decisions, CNC machines can be fantastic long-term investments to improve manufacturing productivity, quality, and profitability.
Adopting CNC machining requires substantial upfront capital investment and ongoing operating expenses. However, the automation, precision, consistency, and production efficiencies enabled by CNC technology can drive major gains for manufacturers. Carefully weighing purchase factors like machine size, capabilities, new vs. used options, and operating costs is key to maximize the value of the investment. With some prudent analysis and planning, manufacturers can implement cost-effective CNC solutions and realize the full benefits of computer-controlled machining for their operations. CNC Milling