Update on Forged Special Steels, Remelting and Powder Metallurgy
Benedikt Blitz, SMR Premium
The presentation will highlight the recent developments in the world of forged special steels and remelted steels (nickel alloys, stainless steel, alloy tool steel, and alloy steel) as well as provide an overview about end-user demand and structures of these special steels. Additionally, the presentation will summarize the actual status of installations (forging presses and remelting units) on a global scale. The speech will also focus on the production of Metal Powders and Powder Metallurgical Steels and especially its associated production technologies like HIP, MIM and AM. As they are and will become key future core technologies for a number of demanding products and thus for the usage in different associated industries. The presentation will also highlight the actual supply and demand situation of metal powders and the manufactured metal powder steels, will introduce leading manufacturers of both powders and steels, and summarizes installed capacity and new capacity that are on the way.
Moldability of Titanium-Based Feedstocks Used in Low-Pressure Powder Injection Molding
Vincent Demers, Ecole de Technologie Superieure
Low-pressure powder injection molding is a cost-effective emerging technology for producing small and complex parts, either in high or in low production volumes. In this study, the moldability of titanium-based feedstocks will be evaluated for it use in low-pressure powder injection molding process. Moldability index of low-viscosity feedstocks will be correlated with real scale injection results. Rheological properties of feedstock formulations will be obtained by mixing Ti-6AL-4V titanium powder with wax-based binder systems. The shear rate sensitivity index and the activation energy for flow will be extracted from the viscosity profiles and used to calculate the moldability index using the Weir’s model. A low-pressure injection press will be used to inject the feedstocks into a spiral and cylindrical mold cavities to measure experimentally the injected length and the flow front profiles. The impact of binders on segregation of feedstocks will be also investigated. This work will focused on the antagonistic effect of surfactant and thickening agents on the moldability properties and segregation of feedstocks for future development and optimization of wax-based feedstocks.
Using Bound Metal Deposition for MIM Prototyping
Animesh Bose, Desktop Metal
Some of the obstacles to further growth for metal injection molding firms are customer acquisition, and tooling prices, and tooling lead times. Desktop Metal has developed a 3D printing process that produces metallic parts via thermoplastic extrusion of MIM feedstocks, followed by debinding and sintering. A high-level overview of the process will be given, along with process capabilities and how MIM firms and customers may use this process to prototype parts, test mold geometries, and speed the time to market of MIM parts, as well as perform short-run production not economically feasible with tooling purchases. Unique aspects of Desktop Metal's process relative to other 3D printing processing will be highlighted.
Process Monitoring and Control Systems as Basic Building Blocks for the 4th Industrial Revolution
Marcel Fenner, PRIAMUS System Technologies LLC
The use of cavity pressure and cavity temperature signals to monitor and control the injection molding process is state of the art in the production of technically sophisticated injection molded parts. The 4th industrial revolution is opening up untold possibilities in the automation of administrative, technical and planning processes. Such control systems are an ideal source of data of the highest relevance and information density.
Depending on the target to be achieved information from many different machines and devices can be collected and analyzed. Some examples are dryers, mold temperature controllers, hot runner controllers, robots, molds, injection molding machines and any other machine or devices with network capability. Specific gains of such systems can be a faster recognition of quality trends and correcting it accordingly, traceability, remote monitoring and controlling or the data is the base for better production planning.
Rationalization of Binders and Debinding
Randall German, FAPMI, San Diego State University
The first patents for powder injection molding date from the 1940s, but the scientific information for binder design and debinding optimization were much delayed. Today, the science of filler and backbone selection involves considerations of monomer type, molecular weight, solubility, first stage binder removal, and second stage burnout (“rest” debinding) without defects or contamination. In certain regards all successful binder systems share some basic features when rationalized in terms of relative melting temperature, internal energy density, powder wetting, and final burnout behavior. A survey of 125 binder formulations illustrates similarities when viewed in terms of binder chemistry, proportions, and phase morphology. Myths on advantages of one binder over another are examined. Finally a few novel formulations arise that build around the fundamentals. Many frustrations would have been avoided if we only knew then what we now know.
Cost Effective Hot Isostatic Pressing—A Cost Calculation Study for MIM Parts
Magnus Ahlfors, Quintus Technologies LLC
Hot Isostatic Pressing (HIP) has been used within the MIM industry for decades for high performance MIM parts. By applying a HIP post process step, pores will be eliminated and the density will increase to virtually 100% of theoretical density. This improves the material’s tensile and fatigue properties and also enables improved quality on machined surfaces.
A great deal of developments has been made on HIP equipment within the last few years allowing the equipment to be more versatile, easy to use, and most importantly, safe and cost effective. This presentation will focus on the cost effectiveness of a modern HIP unit where a cost calculation study has been made on a MIM part production case. The effects of HIP:ing for MIM material will also be explained.
Lean Manufacturing Applications in MIM Value Streams
Michael Borrini, Ruger Precision Metals, LLC
Metal injection molding tends towards batch and queue style operation due to monolith equipment and subcontracted process that reward mass production. Ruger Precision Metals has made a concerted effort to knock down these barriers on our lean journey towards Just In Time manufacturing. Viewing all processes in the value stream as customers, including subcontractors, has led to us to creative solutions that have reduced inventory, cost and arguably most importantly, lead times.
Effects of Molding Parameters on Part Distortion
Lucas Skelly, ARC Group Worldwide
When developing the molding process for new metal injection molded (MIM) parts, it is common to optimize molding parameters such as transfer position, injection velocity, hold pressure and time, and temperature of the mold and barrel to mitigate cracks, flash, shorts, and other visual defects.
The scope of this research will be to determine if the optimization of these parameters can have unintended dimensional effects on the as-sintered part. Furthermore, two different alloys, one gas atomized and the other water atomized, will be investigated to see if there is a difference in sensitivity to these process adjustments based on the powder alloy and type. The as-sintered parts will be analyzed to determine if the molding process optimization has any dimensional effects, and if so, what process parameters are the root cause.
Additive Manufacturing of Ti6Al4V Components to MIM Standards
Mats Persson, Digital Metal AB
Titanium alloys in general and Ti-6Al-4V in particular is one of the most widely applied material in metal additive manufacturing (AM). It is gaining traction in prototypes as well as being selected as preferred manufacturing method in application e.g. medical, dental, aerospace and industrial. The possibility to offer properties in line with component produced by conventional technologies such as Metal Injection Molding opens opportunities for functional prototypes with short lead times and cost efficient small series production. Adding to inherent design freedom and of AM.
Binder Jetting on powder bed is an additive manufacturing process that includes, de-binding and sintering of a green body. With the proper selection of powder and process parameters, properties in lines with components produced by Metal Injection Molding are achieved.
Digital Metal® binder jetting technology was applied for manufacturing of components in Ti-6Al-4V. Layer wise precision binder jetting on powder bed is followed by a curing to develop component’s green strength. Subsequently non-bonded powder is removed and component sintered to develop density and strength. Resulting chemical composition, microstructure and surface finish is reported. Mechanical properties as a function of chemistry and building directions are reported.
Understanding Gating Strategy and the Effects on Characteristics of a Sintered Part
Kevin Backoefer, ARC Group Worldwide
There are several types of gating strategies used in the metal injection molding (MIM) industry. This study will investigate how gate type and location affect the characteristics of molded parts after sintering.
Two identical parts will be molded using two different gate types. Part distortion, density and carbon content will then be evaluated to determine how each gating strategy affects the part, post sinter. The results from this experiment are important for selecting the best gate location for optimized mold designs.
Characterisation of Different Tool Steels made by MIM
Martin Kearns, Sandvik Osprey Limited
Tool steels are growing in popularity for use in MIM applications: exploited for their hardness and wear resistance in harsh service environments. In addition to their use in MIM parts, different classes of tool steels are finding application in 3D metal printing where greater design freedom means that complex inserts can be fabricated featuring, for example, conformal cooling channels, which enhance productivity in high volume injection moulding operations.
Understanding the sintering mechanisms of tool steels is therefore relevant to MIM and emerging 3D printing technologies and it is the purpose of this paper to characterize the moulding and sintering behaviour of a number of popular tool steels. Examples are drawn from hot work tool steels (H11, H13 and DIN 1.2367), shock-resistant tool steel (S7) and high speed steel (T15), covering a range of hardness values, service temperature capability and durability. Results of sintering in nitrogen at different temperatures are presented and related to hardness values and sintered microstructures in the as received and heat treated conditions.
Material Developments in Binder Jet 3D Printing
Andrew Klein, ExOne
As binder jet 3D printing transitions from a prototyping process to a production process for metals, availability of materials is key for increasing adoption of the technology. As was previously presented, breakthrough achievements in printer technology allowed for the printing of standard MIM powders. By leveraging sintering experiences from the MIM industry, it is possible to create more standard metal alloys using 3D printing. This presentation will focus on the development process for new alloys, discuss the qualification process, and present material properties on the latest materials that can be manufactured using binder jet 3D printing.
Now You See It, Now You Don't–The Magic of Dry Ice in MIM Mold Cleaning
Steve Wilson, Cold Jet
No matter how large or small of a molding operation, custom or captive, properly maintaining the mold is the heart of the molding process. Keeping mold cavities clean and vents open is critical for successful molding. It is reported that generally 60-70% of mold maintenance is mold cleaning. With the nature of MIM fouling tooling in just a short number of cycles, how you clean your molds can mean the difference between mediocre performance and high-profit productivity. Traditional methods not only can create extended downtown (because the molds are hot) but can also be ineffective and can cause mold wear to parting lines, sealing surfaces and various surface finishes. This presentation discusses how MIM molds can be cleaned while the mold s are still in the machine, at operating temperatures, in a very quick and effective manner, without causing and wear to the tool.
Dry ice cleaning allows molders to improve productivity and lower cleaning costs by significantly reducing downtime due to traditional cleaning methods. This presentation will also discuss other advantages to cleaning molds with dry ice: improve part quality (no solvent residues left behind), extending the asset life of the tool (non-abrasive), and improving worker safety and the environment by eliminating cleaning chemicals. This presentation will also briefly discuss the theory and process of cleaning with dry ice.
Study of 304L Stainless Steel Magnetic Permeability
Sam Wilmarth, Parmatech
Stainless steel can be categorized in to three main types: austenitic, ferritic and martensitic. 304L is an austenitic type stainless steel, mainly as a result of its 8-12% nickel content stabilizing the austenite phase. Although typically selected for the excellent corrosion resistance properties, a secondary consideration for material selection can be the magnetic properties. A fully austenitic microstructure gives 304L essentially non-ferromagnetic properties but can become slightly magnetic when cold worked. Within the allowable range of Ni content for this alloy, the austenite phase can become less stable under given process conditions. In the case where the low magnetic permeability is a critical property for the material that the component is used for, the chemical composition and processing parameters must be held to a tighter range. A study was performed to define the relationship between chemical composition and process parameter to the magnetic permeability of the 304L stainless steel.
MIM Material Properties of Novel AM Technology
Matt Petros, 3DEO
First announced at MIM2017, 3DEO has developed a novel additive manufacturing technology that closely mirrors the metal injection mold process. However, rather than using a mold to create green parts, the company "prints" green parts. The process uses MIM powders, a MIM-like binder, and a MIM debind/sinter furnace, which means the sintered parts meet MPIF Standard 35.
This presentation will cover three areas. First, a short update of the progress since MIM2017, focused on its technology and part characteristics. The new capabilities of the printers and manufacturing operation will be highlighted. The company will also introduce the audience to its quality metrics of its manufacturing operation.
Second, will discuss how additive manufacturing can be a solution to the problem encountered by every MIM operation -- pre-production parts and legacy part production. Introduction of two case studies on how the company has effectively collaborated with MIM companies in the U.S.
Third, the opportunity to conduct robust analysis of its material properties and part characteristics such as density, surface finish, repeatability, strength, fatigue, chemistry properties will be provided. The majority of the presentation will be dedicated to a discussion of material properties, which will given in the context of real-world applications and case studies. This will be of interest to a MIM audience because most additive manufacturing technologies are very different than MIM, which makes a direct comparison difficult. 3DEO's parts, on the other hand, can be directly compared to MIM.
Study of H900 Heat Treat Parameters of MIM 17-4 PH Stainless Steel
Joshua Carroll, Parmatech
17-4 stainless steel is one of the most popular alloys in MIM production today. This alloy can be strengthened to various degrees with different precipitation hardening heat treatments. The highest strength and hardness heat treatment option for 17-4 PH stainless steel is specified as H900. The processing window both specified in various standards and established by the heat treating industry for wrought products at H900 allows for a large range of many parameters. This experiment explores the effects of different variables within this standard heat treating process window on 17-4 components produced via the MIM process. Variables examined include: solution anneal hold time, solution anneal quench rate, and age hold time. Evaluation includes mechanical testing for relative ductility and micro-hardness.
Predicting Viscosity Behavior for New Feedstock Development in Powder Injection Molding
Paramjot Singh, University of Louisville
To develop new feedstock for powder injection molding (PIM) it is critical to understand the effect of viscosity as a function of solids loading at various shear-rates and temperatures as it can help reduce molding defects such as jetting, and incomplete mold filling. Typically, viscosity measurements are needed to be performed for each solids loading at different shear-rates and temperatures which can be expensive and time consuming. In the current work, a 48, 50 and 52 vol.% AlN feedstock was formulated using a wax-polymer binder system and taken as a basis to measure viscosity for a range of shear-rates and temperatures. Various literature models were evaluated to estimate AlN feedstock viscosity at 48, 50 and 52 vol.% solids loading for specified temperatures and shear-rates. Among evaluated models, the simplified Krieger-Dougherty model had the best fit when compared with experimental measurements with an R2 of 0.64. The lower value of R2 can be attributed to the limitations of simplified Krieger-Dougherty model in predicting shear-rate and temperature effects. In order to improve the viscosity estimates the current work modifies the simplified Krieger-Dougherty equations to account for shear-rate and temperature changes using AlN feedstock viscosity measurements as the basis. It is expected that the current work will help in providing insights for new feedstock development and better mold filling predictions in PIM.
Adoption of 3D Metal Printing in Key Vertical Markets Like Aerospace, Automotive and Medical
Greg Elfering, 3D Systems
This presentation discusses how 3D Systems software and metal printers have been adopted in multiple applications for each following vertical markets:
Jessu Joys, US Metal Powders, Inc.
Jobe Piemme, Praxis Powder Technology Inc.
Influence of Feedstock Property Estimates on Powder Injection Molding Simulations and Experiments of PZT Micro-Pillar Arrays
Sundar Atre, University of Louisville
Powder injection molding (PIM) process simulations can be performed to minimize the number of injection molding experiments by estimating or measuring material properties necessary for PIM simulations. In current work, lead zirconate titanate (PZT) powder-polymer binder feedstock was compounded for 52 vol.% solids loading. Material properties for 52 vol.% PZT feedstock such as physical, thermal, rheological and PVT parameters were estimated using select literature models and polymer binder properties that were measured experimentally. PIM simulations on designed micro-pillar array geometry were performed using 52 vol.% PZT estimated feedstock properties as input parameters. Additionally, PIM simulations were performed to understand the effect of change in micro-pillar spacing on the mold filling behavior. Using PIM simulation results as basis, PIM experiments were performed on designed micro-pillar array geometries to understand the effectiveness of PIM simulations with the use of estimated feedstock properties in predicting molding behavior that have micro-features. It is expected that the results from current work will help in reducing the number of experiments needed to obtain a defect free PIM products.
Lane Donoho, Advanced Metalworking Practices
Developing Binder-Jet AM Technology: Leveraging MIM
James W Sears, PhD, Manager, Carpenter Technology Corporation
A critical review of the binder-jet technology will be provided with an emphasis on the correlation with metal injection molding. The contrasts between the two techniques will be provided. The intent is to use the material properties produced by metal injection molding as a base-line for binder-jet processing.