Metal Injection Molding/Powder Injection Molding

Using supercritical fluids (SCF) for debinding in metal injection molding

Metal injection molding, or MIM, is a manufacturing process which combines the versatility of plastic injection molding with the strength and integrity of machined, pressed or otherwise manufactured small, complex, metal parts. The process involves combining fine metal powders with binders which allow the metal to be injected into a mold using standard plastic injection molding machines. After the part is molded and before the binders are removed, the part is referred to as a 'green part'. The next step is to remove the primary binder. The resultant metal part, ‘brown part’, is sintered at temperatures great enough to bind the particles but not melt the metal and deforming the part. The products of metal injection molding are up to 98% as dense as wrought metal and used in an increasingly broad range of applications. The advantage of metal injection molded parts is that very complex parts that are difficult or even impossible to otherwise fabricate can be manufactured in large quantities.

Traditional debinding methods such as thermal debinding, water solublization, solvent solublization and catalytic debinding are

• environmentally unfriendly due to high VOC emissions
• may use solvents that are scheduled to be outlawed by the Montréal protocol
• have excessively long debinding times.

Advantages of Debinding with Supercritical CO₂ (SC-CO₂ )

• Faster debinding
  
  • Because SC-CO₂, unlike a liquid, has no surface tension, it permeates deeper into the part and dissolves the primary binder quicker and more completely
  • Since the debinding is faster, larger parts can be economically fabricated
• Environmentally friendly
  
  • NO VOC emissions
  • No prohibition by the environmental treaties
  • No increase in greenhouse gases. The supercritical debinding uses existing CO2, no additional CO₂ is created.

Want to learn more? Contact us and we'll help you incorporate Green Chemistry with Supercritical Fluids into your processes!

Read about the other ways SCF is being used. Supercritical Fluids will change the way you work!

Applied Separations offers a full line of SFE systems to meet the needs in your laboratory.

Spe-ed SFE Prime
Applied Separations has created the first teaching tool for Supercritical Fluids. Safe and affordable, this instrument is perfect for the classroom.

Supercritical Fluids (SCF) Education
As thought-leaders in the world of Supercritical Fluids, Applied Separations strikes to share its knowledge and experience to further the use of Supercricial Fluids.

Laboratory Instruments
Applied Separations has the instruments you need in your laboratory to handle the most complex to the most straight-forward SCF projects.

Pilot Plants: Small Production
The basic supercritical pilot plant is a "no frills" caster-mounted system for the budgetminded. You, as the user, determine the size of the system...

Industrial Scale Production
Applied Separations will work with you to pin-point your needs and determine the feasibility of your project.

Metal Injection Molding
Supercritical Fluids will revolutionize the debinding process.

Accessories
Not only do we offer SCF instruments, but a full line of accessories the customize your SCF instruments are also available.

Applications
We have compiled a comprehensive list of SCF applications available for free. Click here to view the list of the SCF applications you can put to use immediately in your lab.

Meet Green-I-Am

Technology Overviews: What is Supercritical Fluid Extraction: A look at this green technology that uses SCF How to pack a vessel: Learn how to effectively pack a vessel for any of the Spe-edSFE instruments in our line. The Spe-ed SFE Prime from Applied Separations: Learn about this low cost instrument, created especially for the educational market. Teaching Environmentally Benign Extraction Technologies with a Cost Effective, User Friendly Instrument: This paper, presented at ACS 2008, describes the fundamentals of the supercritical fluid extraction process and the implementation of this environmentally friendly, green chemistry technique, using the low cost, student-friendly Spe-ed SFE Prime. The "Green" Extraction of Oils from Natural Products Using Supercritical Fluids: Learn how to use SCF for natural product extractions from this poster, presented at ACS 2008. SCF Product Line from Applied Separations: Check out the extensive line of Spe-edSFE instruments available from Applied Separations.    More on ASInteractive...

What is SCF? Carbon dioxide is in its supercritical fluid state when both the temperature and pressure equal or exceed the critical point of 31°C and 73 atm (see diagram). In its supercritical state, CO2 has both gas-like and liquid-like qualities, and it is this dual characteristic of supercritical fluids that provides the ideal conditions for extracting compounds with a high degree of recovery in a short period of time. By controlling or regulating pressure and temperature, the density, or solvent strength, of supercritical fluids can be altered to simulate organic solvents ranging from chloroform to methylene chloride to hexane. This dissolving power can be applied to purify, extract, fractionate, infuse, and recrystallize a wide array of materials. Because CO2 is non-polar, a polar organic co-solvent (or modifier) can be added to the supercritical fluid for processing polar compounds. By controlling the level of pressure/ temperature/ modifier, supercritical CO2 can dissolve a broad range of compounds, both polar and non-polar.