Krajnji vodič za CNC obradu materijala

1. Uvod

U današnjem proizvodnom okruženju, CNC (Računalno numeričko upravljanje) machining stands as a pivotal technology that enables the production of highly precise and complex components.

Međutim, the success of any CNC project heavily depends on selecting the right material.

The appropriate choice can significantly impact the performance, izdržljivost, koštati, and overall efficiency of the final product.

This blog post aims to provide an in-depth guide to CNC machining materials, exploring their properties and how they influence the machining process.

2. Understanding Material Properties

Before exploring specific materials, it’s crucial to understand how material properties impact CNC machining.

Different materials behave differently under machining conditions, and choosing the right material is essential for achieving optimal results.

Here are the key material properties that influence CNC machining:

Tvrdoća

Hardness is the ability of a material to resist indentation, češkanje, I nositi.

Harder materials generally offer greater resistance to wear, making them ideal for parts that will experience abrasion or stress over time.

Međutim, harder materials can be more challenging to machine due to their resistance to cutting tools.

• Ključna razmatranja: Materials like hardened steel, titanijum, and tool steels are known for their high hardness, which makes them ideal for heavy-duty applications.
  Na strani, softer materials like aluminum or plastics are easier to machine, but they may wear down more quickly when used in high-stress environments.
• Primjer: For CNC machining, materijali poput H13 alatni čelik (hardness around 45-50 Hrc) are often used for molding or heavy-duty tooling,
  dok 6061 aluminij (with a Brinell hardness of about 95) is softer and more machinable.

Žilavost

Toughness refers to a material’s ability to absorb energy and deform without fracturing.
It’s a combination of strength and ductility, making it a crucial property for parts exposed to high-impact or shock loads.
Tough materials perform better under conditions that involve sudden forces or mechanical shock, such as automotive or aerospace components.

• Ključna razmatranja: Materials that are both strong and tough can withstand impacts, vibracije, and high-stress conditions.
  Metali poput titanijum i ugljični čelik are known for their toughness and are used in industries requiring reliable and durable parts, such as aerospace or heavy machinery.
• Primjer: Legure od titana (takav Ti-6AL-4V) are highly tough, offering excellent strength-to-weight ratios while resisting cracking under stress.

Duktilnost

Ductility is the ability of a material to undergo significant plastic deformation before breaking, usually through stretching or bending.

High ductility is important for parts that need to be shaped, bent or stretched during the manufacturing process or in use.

It’s especially critical when the material needs to absorb stress without failure.

• Ključna razmatranja: Ductile materials can be easily formed and manipulated without cracking.
  For CNC machining, ductile materials are preferred for applications that require complex shapes or parts that need to bend or stretch without breaking.
• Primjer: Bakar i aluminij are both highly ductile and can be easily shaped into intricate components like electrical connectors or thin-walled parts.

Jačina

Strength is the material’s ability to withstand an applied force without breaking or failing.

The greater the material’s strength, the more weight or pressure it can support without deformation.

For CNC machining, understanding strength is essential for selecting the right material for structural or load-bearing parts.

• Ključna razmatranja: Materials with higher tensile strength (the resistance to being stretched or pulled apart) are ideal for parts that will endure significant mechanical stress.
  Na primjer, titanijum i ugljični čelik are used for their exceptional strength in aerospace and automotive applications.
• Primjer: 7075 aluminij, known for its high tensile strength of 83,000 psi, is commonly used in aerospace, dok nehrđajući čelik offers excellent strength and resistance to fatigue.

Otpor korozije

Corrosion resistance is the ability of a material to resist chemical degradation caused by environmental factors like moisture, sol, ili kemikalije.

Materials that exhibit excellent corrosion resistance are necessary for applications exposed to harsh environments, kao što su morski, kemijski, or outdoor applications.

• Ključna razmatranja: Choosing materials with high corrosion resistance ensures the longevity and durability of the final product.
  Nehrđajući čelik (posebno 316), titanijum, i aluminij are commonly chosen for their excellent corrosion resistance properties.
• Primjer: 316 nehrđajući čelik is highly resistant to corrosion from chlorides and other chemicals, making it a top choice for marine environments and medical implants.

3. Factors to Consider When Choosing CNC Machining Materials

Choosing the right material for CNC machining is a balancing act, considering multiple factors that will affect both performance and cost. Here are the most critical factors to consider:

Izdržljivost

Durability is the material’s ability to withstand wear, korozija, and fatigue over time.

In applications where components are exposed to harsh environmental conditions, durability is a primary concern.

Highly durable parts require less frequent replacements, reducing the total cost of ownership and ensuring long-term functionality.

• Ključna razmatranja: Look for materials that combine both strength and resistance to environmental factors like moisture, kemikalije, i ekstremne temperature.
  Nehrđajući čelik i titanijum are highly durable and resistant to corrosion, making them ideal for medical devices, morsko okruženje, i zrakoplovne primjene.
• Primjer: Legure od titana are commonly used in aerospace and medical industries for their ability to withstand harsh environments without degrading over time.
  Nehrđajući čelik legure poput 316 are also highly durable and corrosion-resistant, making them ideal for equipment exposed to saltwater or chemicals.

Obradivost

Machinability refers to how easily a material can be cut, oblikovana, or finished during the CNC machining process.
Materials with high machinability require less energy to process, which can result in faster production times, dulji vijek trajanja alata, and reduced overall machining costs.

• Ključna razmatranja: Materials that are too hard or abrasive can wear out cutting tools quickly, increasing the overall cost and machining time.
  S druge strane, softer materials tend to machine more easily but may wear down faster in service.
  Aluminij i mesing are known for their excellent machinability, making them cost-effective and efficient for mass production.
  Obrnuto, tvrđi materijali poput titanijum ili Udruživanje require specialized tools and slower machining speeds.
• Primjer: 6061 aluminij is widely used in CNC machining for its ease of machining and ability to produce precise parts quickly,
  dok titanijum demands more attention due to its tougher nature and higher tooling costs.

Toplinska svojstva

Thermal properties are crucial when selecting materials for applications exposed to high temperatures or significant temperature fluctuations.
These properties include thermal conductivity, otpornost na toplinu, and thermal expansion. Materials with poor thermal properties can distort, weaken, or fail under temperature changes.

• Ključna razmatranja: If your application requires components that will be exposed to heat, you’ll need a material with high thermal resistance and low thermal expansion.
  Titanijum i Udruživanje are ideal for high-temperature environments, such as aerospace or turbine applications, where maintaining material integrity under extreme heat is critical.
  Materijali poput aluminij are good for heat dissipation due to their high thermal conductivity.
• Primjer: Udruživanje is often chosen for its ability to withstand extremely high temperatures (up to 2,000°F) bez gubitka mehaničkih svojstava.
  Aluminij (kao 6061) is often used for heat sinks and thermal management components because of its excellent thermal conductivity.

Koštati

Cost is often one of the most critical factors when selecting CNC machining materials, especially for large-scale production runs.
Materijali poput aluminij i mesing are more cost-effective compared to specialty materials like titanijum ili Udruživanje.
Međutim, selecting a cheaper material may lead to compromises in performance or longevity, so it’s important to balance cost with the required performance standards.

• Ključna razmatranja: Consider not just the upfront material cost, but also factors like machining time, nošenje alata, and potential maintenance or replacement costs over the long term.
  For low-cost, aplikacije velikog volumena, aluminij i plastika takav akril i najlon are often used.
  For high-performance parts, the additional cost of materials like titanijum may be justified.
• Primjer: Aluminij 6061 is often chosen for its excellent balance between cost and performance, especially for structural and lightweight parts in industries like automotive and aerospace.
  Titanijum, dok je skuplji, is selected for its unique properties in demanding applications such as aerospace and medical implants.

Finish Requirements

The finish requirements of a part can significantly influence the material choice.

Materials that offer better surface finishes with minimal additional post-processing are preferred for applications where aesthetics

or functional surface properties (like smoothness, otpor korozije, or conductivity) su kritični.

• Ključna razmatranja: For parts that require a high-quality finish, materijali poput nehrđajući čelik ili aluminij are easier to polish and anodize, pružajući čistu, visually appealing result.
  Other materials, takav alatni čelici i Udruživanje, might require additional processing steps like grinding or polishing to achieve the desired finish.
• Primjer: Aluminij 6061 is popular for its ability to take a high-quality finish, whether anodizing, praškasti premaz, or simple polishing.
  Nehrđajući čelik, posebno 304 ili 316, is often used in applications where a shiny,
  aesthetically pleasing finish is required, such as kitchen appliances or architectural components.

Industry Application

Different materials are tailored for specific industries, depending on the performance requirements and environmental conditions.

Understanding the specific needs of the industry is critical when selecting CNC machining materials.

• Ključna razmatranja: Each industry may prioritize different material properties. Na primjer, zrakoplovstvo requires materials with high strength-to-weight ratios and heat resistance,
  medicinska primjena demand biocompatibility and corrosion resistance, i Automobilski dijelovi benefit from cost-effective, izdržljivi materijali.
• Primjer: u zrakoplovstvo industrija, materijali poput titanijum i Udruživanje are favored for their high strength-to-weight ratio and resistance to high temperatures,
  dok medicinski implantati often rely on nehrđajući čelik ili titanijum due to their corrosion resistance and biocompatibility.

4. Common CNC Machining Materials

Let’s break down some of the most commonly used materials in CNC machining, kategorizirani prema vrsti:

Metali:

• Aluminij (Npr., 6061, 7075): Aluminij je lagan, otporan na koroziju, i lako se obrađuje, making it one of the most popular choices.
  Na primjer, 6061 aluminum has good strength, i dobra otpornost na koroziju, and is often used in the aerospace and automotive industries.
  S druge strane, 7075 aluminij, with its higher strength-to-weight ratio, is preferred for high-performance applications like aircraft parts.

• • Svojstva: Jačina: 30-50 ksi (za 6061), Obradivost: Izvrstan
  • Prijava: Zrakoplovstvo, automobilski, proizvodi široke potrošnje.

• Nehrđajući čelik (Npr., 304, 316): Stainless steel is strong, izdržljiv, i otporan na koroziju, which makes it perfect for demanding environments like food processing, medicinska oprema, i morske aplikacije.
  Na primjer, 304 stainless steel is one of the most widely used grades due to its excellent corrosion resistance and relatively lower cost.

• • Svojstva: Jačina: 70-100 ksi, Otpor korozije: Izvrstan
  • Prijava: Medicinski, prerada hrane, morski.

• Titanijum: Titanium alloys are known for their high strength-to-weight ratio and resistance to corrosion.
  Titanium is commonly used in aerospace, medicinski, and military applications where performance and reliability are critical.

• • Svojstva: Jačina: 130-160 ksi, Obradivost: Težak
  • Prijava: Zrakoplovstvo, medicinski implantati, vojnog.

• Bakar & Mesing: Copper is excellent for electrical conductivity, while brass is known for its corrosion resistance.
  These materials are commonly used for electrical and plumbing components.

• • Svojstva: Provodljivost: 58% IACS (Bakar), Jačina: 50-70 ksi (Mesing)
  • Prijava: Električni priključci, vodovodne instalacije.

• Ugljični čelik: Carbon steel is strong, isplativ, i svestran. It’s commonly used for structural components and parts that don’t require extreme corrosion resistance.

• • Svojstva: Jačina: 50-70 ksi, Koštati: Nizak
  • Prijava: Automobilski, konstrukcija, general manufacturing.

Plastika:

• Akril (PMMA): Acrylic is lightweight, transparentan, i lako se obrađuje, making it an ideal choice for applications like signage, rasvjetna tijela, i prikazuje.

• • Svojstva: Obradivost: Izvrstan, Otpor udara: Umjeren
  • Prijava: Displays, signalizacija, optical lenses.

• Najlon: Nylon is a tough, wear-resistant plastic often used for gears, čahure, and moving parts in machinery.

• • Svojstva: Jačina: 10-15 ksi, Nositi otpor: Izvrstan
  • Prijava: Zupčanici, ležajevi, automobilski.

• Delrin (Acetal): Delrin is a high-strength plastic known for its rigidity and precision. It’s often used for parts requiring tight tolerances, kao što su zupčanici i ležajevi.

• • Svojstva: Jačina: 20-25 ksi, Dimenzijska stabilnost: Izvrstan
  • Prijava: Precizni dijelovi, zupčanici, ležajevi.

• Polikarbonat: Polycarbonate is known for its impact resistance and is used in applications requiring toughness, such as protective covers.

• • Svojstva: Otpor udara: Vrlo visok, Transparentnost: Izvrstan
  • Prijava: Protective covers, optical lenses.

Kompoziti:

• Karbonska vlakna: Carbon fiber is incredibly lightweight and strong, making it ideal for high-performance applications in industries like aerospace and sports equipment.

• • Svojstva: Jačina: 150-300 ksi, Težina: 30-50% lakši od aluminija
  • Prijava: Zrakoplovstvo, automobilski, sportska oprema.

• Stakloplastika: Fiberglass offers strength and resistance to corrosion, commonly used for structural applications and parts exposed to harsh environments.

• • Svojstva: Jačina: 40-80 ksi, Izdržljivost: Visok
  • Prijava: Čamci, strukturne komponente.

5. Specialty CNC Machining Materials

Udruživanje

They are designed for high-temperature resistance, making them indispensable in aerospace and power generation sectors.
Udruživanje 718 can withstand temperatures up to 700°C, ensuring stability in extreme conditions.

Hastelloj

It is highly corrosion-resistant, particularly in aggressive chemical environments, and is frequently used in marine and chemical processing industries.
Hastelloy C-276 exhibits excellent resistance to pitting, korozija pukotine, and stress-corrosion cracking.

Keramika

Ceramic materials are exceptionally hard and wear-resistant, suited for applications like cutting tools, ležajevi, and semiconductor manufacturing.

Silicon nitride ceramics, na primjer, have a hardness of 15 GPA, providing outstanding durability and longevity.

Alatni čelici

Tool steels are specifically engineered for molds and dies, offering outstanding hardness and toughness for high-stress applications.

A2 tool steel, with a Rockwell hardness of HRC 60-62, ensures reliable performance in demanding manufacturing processes.

6. Dodatni čimbenici koje treba uzeti u obzir

Tolerances Required

Tight tolerances necessitate using materials that machine predictably and hold dimensions accurately.

Precision engineering often requires tolerances within ±0.001mm, which can be achieved reliably with materials like titanium and stainless steel.

Post-Machining Processes

Some materials benefit from or require post-machining processes such as heat treatment, premazivanje, odnosno poliranje.

These processes can enhance material properties or aesthetics. Na primjer, anodizing aluminum not only improves its corrosion resistance but also adds an attractive finish.

Uvjeti okoline

The operating environment of the component should be considered, including exposure to chemicals, vlage, UV zračenje, i temperaturne fluktuacije.

Polikarbonat, na primjer, offers excellent UV resistance, making it suitable for outdoor applications.

7. How Material Selection Affects CNC Machining

Vrijeme obrade

Harder materials generally take longer to machine, potentially increasing production costs and lead times.

Na primjer, machining titanium can extend machining time by up to 30% u usporedbi s aluminijem, impacting overall efficiency.

Nošenje alata

More abrasive materials can accelerate tool wear, leading to higher maintenance costs and frequent tool replacement.

Using diamond-coated tools can extend tool life by up to 40%, smanjenje vremena zastoja i troškova.

Površinski završetak

Certain materials inherently produce better surface finishes, reducing the need for additional finishing steps and improving overall efficiency.

Delrin, na primjer, can achieve surface roughness values as low as Ra 0.8 µm, minimizing post-processing requirements.

Troškovna učinkovitost

Balancing material cost with production efficiency is crucial.

Expensive materials might justify their cost through improved performance or reduced machining times, while cheaper alternatives could lead to higher long-term expenses if they require more extensive processing.

Na primjer, choosing aluminum over titanium can reduce initial costs but may result in higher maintenance and replacement costs over time.

8. Zaključak

Selecting the appropriate material for CNC machining is a critical decision that impacts every aspect of the project—from initial design to final performance.

By understanding the properties and considerations involved, manufacturers can choose materials that best meet the demands of their application while balancing cost and efficiency.

Choosing the right material not only enhances the quality and durability of the final product but also optimizes the entire manufacturing process.

Embrace the precision and potential of CNC obrada by making well-informed material selections, and elevate your projects to new heights.

DEZE je profesionalna tvornica za CNC obradu. If you have any CNC processing needs for any material, Slobodno kontaktirajte nas.