How we chose our latest service vehicle
With SolidWorks and Stratasys service staff and consultants traveling all through New England, CAPINC has a small fleet of sedans and light trucks to help minimize our transportation costs. The newest addition to this fleet is a 2014 Chevrolet Cruze Diesel.
The Cruze is a mid-sized sedan built in Lordstown Ohio and other plants around the world. The 2.0 liter turbodiesel is supplied by GM Germany, while the six speed automatic is made by Aisin in Japan. As a result, while the car is “American” the American content is 50% plus 16% Mexican content. The diesel comes with a high level of standard equipment: the price difference compared to a similarly equipped gas model is between $2,000 and $3,000.
Especially in Northern New England, most of our driving is on highways and there diesels really shine: the EPA highway rating is 46mpg. The diesel model has some of the aerodynamic features of the Eco model, with under-car panels to smooth airflow, a small rear lip spoiler, and active grill shutters. These shutters remain closed unless additional cooling air is needed. Reducing airflow into the engine compartment helps reduce drag.
Having been a Cavalry platoon leader with nine diesel combat vehicles, I had a few concerns about diesels: noise, cold starts, and sluggish performance. Chevrolet has addressed these issues effectively. The typical “diesel clatter” is noticeable at idle from outside the car, but around town and on the highway it is muted. GM upgraded the engine with ceramic glow plugs and even at temperatures below zero, the glow plugs only need a few seconds to start the car. While the horsepower rating is modest (150hp) this engine has torque of 250 ft lbs and a special “torque boost” mode that will allow up to 280 ft lbs for 10 second periods. The car accelerates from 0-60mph in 8.6 seconds and easily keeps up with traffic at all highway speeds.
The best-selling diesel passenger car in the US is the Volkswagen Jetta TDI, which also features a 2.0 liter turbodiesel. Dimensionally the cars are nearly the same length and width, while the Cruze is a few inches lower. The Cruze is also a little heavier but has a larger fuel tank (15.6 gallons). We buy U.S. assembled cars and while the Passat TDI is now built in a factory in Tennessee, the Jetta Diesel is built outside the US and was thus not considered.
Now that we’ve lived with the Cruze TD for a few weeks, we’ve formed some strong impressions. First, the interior is excellent and the front seats extremely comfortable. Second, the factory navigation system and “Infotainment” system is easy to use and very well integrated relative to some other factory installations. (We purchased that option as some states require “hands free” cell phone use and we want to minimize distraction). Mileage is living up to expectations, with a range of 31 to 51 mpg in city, commuting, and highway use. Ride is well controlled without being harsh.
We normally keep company cars for the five year depreciation period, during which we rack up 120,000 to 180,000 miles. Along with the operating economy and fuel range, we expect the resale value of this car to be higher than the four cylinder gas version.
Some of the upgrades we’ve added so far:
General Altimax Arctic winter tires
We equip all our company cars with winter tires because of the immense gains in stopping and handling over all season tires. We normally purchase Nokian (and prefer the new Hakkapeliitta R2) or the Michelin X-Ice but these tires were sold out. The Altimax Arctic is the Gislaved Nord Frost 3 – a well regarded performer at very competitive cost.
WeatherTech Floor Liners.
Most OEM rubber mats have flat sides, dumping the pool of ice, snow and salt that melted off your boots onto the edges of the carpet. Weathertech molds liners with substantial edges that contain the mess and protect the car. They now use digitizers to scan each car model to provide a custom fit.
Exploiting the fame generated from design of a 3D printed plastic gun, a DMLS (Direct Metal Laser Sintering) service bureau has now produced a metal 3D printed gun. Solid Concepts, a California-based service bureau, used the EOS process to build the parts. The press release indicates the gun was built in Texas, likely due to California's complex-if-ineffective gun laws.
DMLS uses layers of metal powder. A relatively high-powered laser is focused on a region, fusing it. A recoater then applies another layer of powder and the process is repeated. The primary differences with plastic layers processes lies in the power required and the thin layers (about 20 microns, less than one one thousandth of an inch), and the very high cost of the systems. But even very tough-to-machine alloys and materials like Cobalt steel and Titanium can be used, so the primary applications for this process thus far have been for medical and aerospace products with complex geometry.
The gun produced was a classic M1911 pistol, designed by John Browning and the U.S. military's official sidearm for nearly 80 years. According to the company, over 30 parts (of a total of 50+) were made using DMLS, including the rifled barrel. Unlike Cody Wilson's Defense Distributed, Solid Concepts has a Federal Firearms License for manufacturing, and did not release any designs.
So will 3D printed metal guns catch on? The economics don't favor it anytime soon. Using a $600,000+ industrial system to produce a part you can buy for $50 seems like a "get rich slow" program to me. If you are in the market, I'd suggest purchasing one instead from Connecticut-based Colt Manufacturing, New Hampshire based Sig Sauer, or Massachusetts-based Smith & Wesson. Or a Veteran such as this M1911A1 produced by the Remington Rand typewriter company in WWII.
Although we’ve been selling and supporting 3D printers for nearly 10 years and now have many customers with multiple systems, a lot of our new business comes from businesses who are buying their first 3D printer. For these new buyers, the intertwined risks of investment and technology can be paralyzing. At the front of their minds is often the idea that “We don’t want to buy something that’s obsolete.”
Well – relax! Because any 3D printer you buy is already obsolete. So make sure the investment makes business sense anyway.
Last week I purchased an Apple iPhone 5. I’m well aware that Apple is introducing the 5S and 5C models in mid-September. And there is no question that the 5S is “better” than the 5. But the new features are not something I use all day, every day. The cost of the new phone will likely be higher, it wasn’t available for at least a month, and there is some risk of teething problems attendant in the introduction of any new, complex product. For me, the costs of missing customer calls on my aging Android phone, the increased utility of some of the apps shared with an iPad, and the proven reliability of the product made it the right business decision – even though it is “obsolete.”
The consumer products industry in general and the fashion industry in particular are built upon a strategy of planned obsolescence: the time frame for becoming obsolete is built into the product. More complex and expensive products like automobiles use a strategy of “Continuous detail improvement” so that, while the old product remains usable, new product features are regularly introduced so that the new model becomes increasingly attractive. The vehicle we purchased in 2006 remains perfectly useful – even though it does not have any means to hook up an MP3 player and relies on radio or CD’s. The 2009 model has an MP3 connection and can also play DVD’s – but no Bluetooth integration like the latest models. So all three models perform the basic task of transportation, and newer models probably last longer, but those without the latest features are less appealing to consumers.
Far more likely in the 3D printer industry is what might be waggishly called “Unplanned obsolescence.” Innovations in the industry have disrupted established markets a number of times. In 2004 Stratasys introduced the Dimension systems at a price point of $30,000, supported by local dealers. This was about 40% of the price for similar capability the year prior. Over 300 systems were sold in the first year at a time when most manufacturers sold dozens of systems a year.
Rapid obsolescence comes with a significant danger to system manufacturers: prospective customers will delay purchase. So system manufacturers have adopted more flexible architectures that accommodate new materials or electronics, and/or implemented extremely generous trade-in policies. Customers can generate sufficiently high returns on investment to justify initial purchase, without being penalized for early adoption.
The explosive growth of the low-cost “maker-grade” systems has called into question the value of professional systems, which now comprise the market space from $10,000 up. But this ignores the very real difference in capability between even the very best maker-grade systems and the least-expensive professional systems. Maker systems thus far have supported hobbyists interested in exploring a new technology but without any business objective to support.
By contrast, professional systems support paid employees developing products where time-to-market is king. The systems are expected to run uninterrupted for days to support rapid product development.
In our experience, prospective customers tend to assume that price points will decline over the long term. While this may be true, in the short run, system manufacturers generally use a different pricing strategy. They establish price points ($10,000, $25,000, $50,000, and so on) that recognize the various levels of authority to “sign-off” such an investment within corporate design environments, and continue to add features over time to keep the offering competitive. So five years from now, a $25,000 printer may be faster and more capable – but there will still be offerings at that price point.
One frequent topic of conversation as we plan for the future is “How do we make our customers most productive?” Two factors that significantly impact these planning discussions:
1) Measuring CAD user productivity is difficult!
2) All CAD users consider themselves "Experts"
At SolidWorks World each year, there is a Model Mania competition where users are timed on a standard task, including changes and sometimes an FEA run. CAPINC’s Engineering Manager Jason Pancoast is a two-time worldwide winner and runner-up a third year; we believe a VAR must be able to use the tools to their fullest potential to be able to teach them.
The breadth and depth of tools in SolidWorks can be overwhelming to new users. There are comprehensive tools for solid modeling, surface modeling, sheet metal design, drafting, assembly, and data import/export. Scratch the surface only a little and you add assembly animation with interference checking; tolerance analysis, rendering, and costing. Dig a little deeper and you add FEA (Finite Element Analysis) and PDM (Product Data Management).
SolidWorks includes online help and tutorials, and there are number of tools that augment these offerings, from for-fee testing and video to free YouTube videos, dealer telephone support, and programs like CAPUniversity. So with the financial commitment, time away from project work, and general nature of classroom training, it should be dead in the 21st century – right?
Not So Fast!
There are a number of factors that are making product development professionals reconsider more formalized training regimens:
1) Engineering staffs are at an all-time low, everyone is expected to do more
2) Product development lead times are never fast enough
3) Quality requirements are greater than ever
4) Almost everyone faces worldwide competition
Tutorials help users understand the tools. They seldom address what might be called “Design Strategy”. Designing a project from concept through production requires consistent practices throughout. There is one area where classroom training delivers real benefits.
The primary benefit of classroom training, though, seems to be the old adage that “You don’t know what you don’t know.” The classroom training environment remains unmatched in that questions and comments by others prompt additional insights into how to use the tools.
If someone commented “Well, Dana, you sell classroom training – you’re not exactly unbiased.” And that is fair commentary: we recently spent $100,000 on new Hewlett Packard workstations to equip four training centers, so we have a significant investment in that environment.
What we see is a real interest in making users more productive, for all of the reasons listed above. One trend we’ve noticed is that training is often a leading indicator of the economy: if business is on the upswing, companies spend more on training, while if the economy is slowing down, we see a decline. Based on that theory, we can expect continued slow growth in the economy into 2014.
The most significant trend we’ve seen lately, though, is an uptick in customized training. Increasingly, mid-sized and larger groups are signing up for intensive sessions tailored to their specific design environment. So based on these customer preferences, at least for the next few years, classroom instruction will remain an important tool in optimizing your product development process.
Commercial 3D printers have been aimed at corporate and professional users since their invention in the late 80’s. Like any other semiconductor-based technology, price/performance has improved over the years. For a given build chamber size, prices are now approximately one quarter of what they were in 2004 but these systems are still out of reach for anyone but commercial users.
This changed in 2005 when Dr Adrian Bowyer started a project at the University of Bath to create a “Self Replicating Prototyper.” The project was called “RepRap” and used a process called “Fused Filament Fabrication” to avoid a trademark dispute over the use of FDM (Fused Deposition Modeling). FFF is a similar approach and relied on that fact that certain key Stratasys patents had expired. These machines were (and remain) open source systems that relied on crowd sourced hardware and software.
The RepRap project developed four different models that cost as little as $350 in kit form. There are now at least 25 different suppliers of kits or systems, including fully assembled models. Some have branched off into proprietary hardware or software in an effort to create intellectual property or differentiate themselves. They top out in price at around $3,500.
The Proactive 3D Printer Consumer
With the least expensive professional models costing $10,000 or more, here comes the “Prosumer market.” Prosumer is a term coined by Alan Toeffler in 1980 as a contraction of “Proactive” and “Consumer” to mean someone who actively participates in the design and improvement of a product they use. It has since taken on multiple meanings first as “Professional Consumer” (notably in the camcorder and digital camera market) or someone who desires or requires product features of professionals while using the product personally. The term has since been used in a third way: “Producing Consumers” or those who are actively customizing mass-produced goods for their own needs.
From a marketplace perspective, system marketers are trying to fill the gap between the $2,500 “maker” systems and the $10,000 and up commercial systems. One obvious candidate is MakerBot, recently acquired by Stratasys in a stock deal. Using Stratasys extruder, software, and build chamber technology, MakerBot could potentially provide a system in this price rang that would be sold directly by the manufacturer.
While most of the systems on the market are based on FDM technology, there are others. Form One is a Cambridge, MA based startup building a $3,500 system based on UV cured photopolymer. These systems have only recently started shipping so there isn’t much user feedback as yet. In addition, 3D Systems has filed a lawsuit against them alleging patent infringement. No matter the outcome, others will attempt to fill this market segment.
The Maturing Marketplace
Currently there are almost no systems available in the price range from $2,500 to $10,000. Don’t expect this vacuum to remain for very long. Whether these newly offered prosumer systems will be commercially successful is another question entirely. They may prove too expensive for consumers while proving too slow or having properties insufficient for commercial use. But there will be new such entries, without question.
Press references to “3D Printing” have increased by two orders of magnitude in the last two years as the technology – and low-cost maker-grade devices – capture the popular imagination. Many of these newly interested do not understand the roots of the industry in the 1980’s and what some of the short and long-term potential really is.
Building products up to chair size out of one or two materials is already not only possible but commonplace. But what are some of the real, world-changing applications on the near horizon?
Larger and larger systems are being built, increasing the types of applications: current commercial systems are available up to about 4 feet by four feet by eight feet, allowing production of parts as large as automotive dashboards.
Several groups are experimenting with additive manufacturing systems designed for buildings, and a number of UAV’s (Unmanned Autonomous Vehicles, or “Drones”) have been designed and built – one with 3D printed circuitry as well as airframe.
One of the most ambitious and forward-looking projects is “4D” [Four Dimensional] printing, which adds a fourth dimension to the build: time. The concept is very simple. A model is built in a 3D printer. Once the model is built, additional inputs can be applied in the form of time and energy. The first examples are self-folding or self-unfolding models that orient themselves. This has potential applications from the human body to space travel.
Stratasys has been actively involved because of one unique capability of the Connex series of 3D printers: their ability to make multi-material parts. The Connex supports “Digital Materials” which can be mixtures of [currently] two materials to tune the physical properties of different areas of the part. These materials are not just mixtures of two materials in different ratios. The system has internal logic to distribute droplets of materials as part of the process.
The MIT Self Assembly Lab, led by Skylar Tibbetts, is the leader in these applications. Here is his TED talk on the subject.
3D Printers bring speed to product development; cost savings are less significant.
Like a lot of active families, we have Thule racks on our car. The bars stick out a bit from the side of the car. Both my wife and I have hit our head on the front rack getting in or out of the car.
Thule makes end caps for their bars and they are only $10 for a set. But they are black – same as the bars. I wanted something that would make the ends of the bars more visible. So I started designing new end caps to be made in yellow ABS on one of our FDM machines.
After some measuring I made an outer section and printed off a piece to test the fit: the bars are covered with a plastic layer so measuring the nominal value didn’t give any assurance of a slip fit. The next version was keyed to the inside of the bar to help hold it in place. Once I got those dimensions right, I was able to build the “final” design which was the fifth iteration.
The models I built took from 12 to 53 minutes to build. The total material cost was less than $10. And the whole process took half a day.
While designers, engineers and managers use cost savings as the justification for bringing a 3D printer in-house, that’s not the best reason. Rather, the best reason is that having a 3D printer in-house accelerates the product development process.
For at least the last ten years, having models 3D printed has become part of the product development process. Because of the costs associated with those models and the lead times required by contractors, they usually only budgeted the time and money for one model cycle. After developing the initial design, it would be prototyped. The models would be studied, changes made, and the project would go to tooling and production. Additional prototypes weren’t made because the time and budget was not available.
As the use of in-house systems has increased, designers are beginning to use these models and partial models as part of the product development process. They are making far more models than ever before. We often ask our customers to estimate how many models they will make in the first six months they own the machine. Their estimate is usually one quarter to one third of the actual total.
So when you are justifying the costs of bringing a 3D printer in-house, the more-appropriate question to ask is “What is it worth to our business to bring our products to market one month sooner? Three months sooner?" Time to market is really 'time to profit'.
One educator we work with added a different perspective. Before they had a 3D printer, the students would create models in a CAD system but had no way to make them. Once they got a 3D printer, they could build and try their designs. Paraphrasing the teacher, “They aren’t designing until they are making.”
New and exciting uses of 3D printers to make custom prosthetic limbs, dentures, UAV’s etc. are publicized every day. None of those applications made quite the splash that Defense Distributed did when they published files for a single shot pistol designed to be 3D printed on a Stratasys FDM system.
I called shenanigans on a prior claim that they’d created a “3D Printed Gun,” noting that all the parts in contact with the cartridge were metal. This time, they actually made a single-shot, one time use pistol entirely from 3D printed parts.
WWII history buffs will recognize the name of the FP-45 Liberator, an inexpensive single-shot pistol designed to be distributed to partisans in occupied territories. The idea was that the mass arming of the civilian populace would hamper the operations of the occupying forces. Only small quantities of the pistol were ever distributed.
Defense Distributed designed this device specifically to open up a number of free speech and related issues. I’d like to stick to one, avuncular topic: “Don’t shoot your eye out, kid.”
There are a number of processes and materials used to make 3D printed parts. There are big differences between the physical properties of a part made on a RepRap or other "Maker grade" machine, different photopolymer-based systems, and the types of large, sophisticated machines used in industry.
Commercial firearms are extensively tested and can withstand proof loads many times higher than normal firing pressures. The test load was not identified, no proof loads were identified, and the stated goal was to fire one round. Firing a cartridge that exceeds the design limits of the gun could result in catastrophic failure and resultant injury.
Should we be worried about terrorists carrying 3D printed plastic guns? Probably not.
The one thing I didn't see in the Defense Distributed test firing is a chronometer, the device used to measure the velocity of a fired bullet. The pistol was designed to fire a .380 ACP cartridge (also known as “9mm Browning” or “9mm Kurz”). Note that no police agencies carry this cartridge: it is not considered powerful enough.
In the US we typically measure the energy of a fired bullet in ft lbs. Kinetic energy varies as the square of the velocity. Put another way, if muzzle velocity is halved, the muzzle energy is one quarter. With a standard commercial brass case and typical loading, these cartridges usually generate up to about 200 ft lbs of energy when fired from a steel pistol barrel of appropriate length: for example, a 90 grain bullet fired at around 1,100 feet per second.
It's not far-fetched to think that a very short plastic chamber and barrel would generate substantially less muzzle velocity than a precision-made steel barrel. A muzzle velocity of 775 fps (70% of test specifications) would reduce the muzzle energy to 100 ft lbs. A muzzle velocity of 550 fps (50%) would further reduce KE to only about 50 ft lbs.
Still dangerous? Of course. But compare that 50 ft lbs of energy to a .22LR. Most .22LR cartridges generate 70+ ft lbs of energy. So you’d have a pistol that could fire one round through an unrifled plastic barrel that was significantly less powerful than a .22.
Finally, while the gun itself is made of plastic, the cartridges are still metallic: brass or steel case and lead or coated lead bullet. So while the plastic itself might not be “detectable” (it’s detectable, but may not be recognized as a gun), the metallic cartridges remain as detectable as before.
So compared to a pistol made by conventional methods, the only real advantage of a 3D printed gun is that you need no skill or experience to download the files and print them. And this appears to be largely the aim of Defense Distributed: to give access to a firearm to anyone. But there is a whole lot more hype than substance to their claims.
Responses to this project have ranged widely. Recently, California Senator Leland Yee announced plans to file legislation controlling this use. Given that a 3D printed gun could not likely be traced back to a particular printer, it’s unclear what this legislation would look like.
And it’s also unnecessary. Most plastic products aren’t made on 3D printers, so the security industry has come up with technology to detect them. In fact, some are even using it to promote their solutions.
EDITORS UPDATE 5/22/2013
As we suspected, once these devices were tested, the realities became apparent:
The muzzle velocity is indeed very low: in one test two rounds recorded 498.2 and 465.1 FPS. This is less than half the muzzle velocity from a commercial steel barrel and would substantially diminish the kinetic energy delivered.
The cases “have to be hammered out of the barrel.” Not surprisingly, when the cartridge is fired the plastic barrel expands, as does the brass casing.
In my previous blog post I explained some of the Pros (design freedom, no tooling cost) and Cons (relatively high material cost, low production rates) of 3D printing processes in general relative to most other production processes. Going a step further, I’d like to explain some specifics of how to optimize a design for end-use using the Stratasys Fused Deposition Modeling (FDM) process.
Specific Disadvantages of the FDM Process
Let’s get the disadvantages of FDM out of the way first. You can use these as “gates” or “filters” to decide if a particular project should be produced with this process.
1. Material costs. FDM material costs very approximately 10 to 20 times what injection molded grade materials cost.
2. Physical properties. Because FDM does not have the pack and hold pressure of injection molding, physical properties for the same basic resins (ABS, Polycarbonate, etc) are often 10-20% lower than the same injection molded part.
3. Surface finish. Depending on the color, material, and layer thickness, FDM parts have a rougher surface finish than injection molded or pressure-formed parts. Cosmetic post processing increases delivered cost.
4. Density. FDM parts have very small voids due to the round bead: a “solid” part is 95-98% dense. Without sealing, the parts will leak pressurized air or liquids.
5. Build Size. In order to build a part without joining, it has to fit in the system you have. One often-overlooked consideration is that the build envelopes have larger dimensions in the 2D and 3D diagonal directions than the spec sheets show. For example, here are the point-to-point 2D and 3D diagonal dimensions of popular FDM systems:
6. Production Rate. FDM is a vector process and building multiple parts increases the build time linearly. Production rate varies with the material, system, system settings, density, and orientation. The highest volumes our customers are producing in the range of tens to low hundreds of parts per month.
Specific Advantages of the FDM Process
1. Variable wall thickness. Unlike most molding processes, FDM parts can accommodate a wide range of wall thicknesses in a single part.
2. Variable density. An advantage of FDM is the ability to “honeycomb” thick wall sections. This allows for a stiff part without excessive material use and build time.
3. No draft or draw requirements. No draft is required for FDM parts. Designs requiring side actions as molded parts are made without concern.
4. Assembly consolidation. The more complex the part, the more competitive FDM will be. Consolidating multiple molded parts into one can result in quality improvements and savings in part and assembly costs.
5. Change Freedom. Because there is no tooling cost and minimal inventory required, FDM parts lend themselves to rapid product improvements and small-batch customization. For high-value electronic products, the ability to change bezels, brackets, housings etc. without long lead times or tooling costs can lead to faster market acceptance and early profits.
6. 3D Printer “Buzz.” The number of press references for “3D Printing” has increased by two orders of magnitude in the last year. Manufacturers like VPI Industries have created a stir by featuring 3D printed structures in their products – and advertising that fact.
A Word About Post Processing
The surface finish of an FDM parts exhibits small striations on the surface as the result of the build process. There are three approaches designers are taking to surface finish.
Design for it. One customer has designed two different colored bezels built in two orientations. The product was designed to reflect light and create its’ own aesthetic – without any post-processing. The product features this look as a kind of “3D Chic.”
Vapor smoothing. The Stratasys Smoothing Station uses a vapor process to smooth parts to a finish similar to injection molded parts, but the process works for ABS only. Others dip the parts in various solutions to help smooth the finish or dull the gloss.
Painting. Many electronic products have other sheet metal or plastic exterior parts that are painted by industrial finishing houses. FDM parts can be painted via these processes without special handling.
Inserts. Threaded inserts can be easily inserted ultrasonically, or by heating the insert with a soldering iron prior to insertion. Drill bushings and other metal parts can be bonded in place, and ins some cases, builds can be paused for insertion of inserts during the build.
Design science for 3D printing in general, and FDM in particular, is advancing rapidly. According the 2012 Wohlers Report, 3D printer material sales increased 50% from 2009 to 2011, with further rapid growth ahead as more production applications take shape. Manufacturers will be well served by investigating the potential benefits of this technology in addition to the now more common uses for prototyping, patterns, jigs and fixtures.
Even prior to President Obama’s mention of additive manufacturing in his second term inaugural speech, 3D printing was being hyped in some circles. This in turn led to a backlash, often including statements that “3D printing is fine for prototypes, but not suitable for ‘real’ parts.”
First of all, while the term 3D Printing has become the popular form of reference, SME (Society of Manufacturing Engineers) currently refers to the umbrella term “Additive Manufacturing” to describe this group of processes. The term “3D Printing” was coined and popularized by the industry to differentiate systems that were suitable for use in an office as opposed to larger systems designed for a shop floor.
End-use parts are routinely made today. Hearing aid uses mass-produced electronics in housings that are made specifically for the patient, leading to the term “Mass customization.” Dental implants are also routinely made via additive processes. Custom prosthetic devices are also relatively common applications today.
While pundits are touting the idea of a 3D printer in every house, design science is only just starting to catch up with the potential of the process. Focusing on plastic parts, here are some of the disadvantages of additive manufacturing (AM) for production applications:
Materials are more expensive - Injection molding grade ABS is around $2.00 per pound. The least expensive AM materials are approximately 10 times that.
Production rates are low - Injection molding machines can cycle in 30 seconds or less. Metal stamping presses are faster still. Even small parts currently take several minutes each to make on AM systems.
Physical properties are not as high - Injection molded parts benefit from high pack and hold pressures for maximum density. In most cases, a part designed for injection molding will not be as strong when made via an AM process.
Asthetics and Finishing - Depending on the process, surface finish may not be what the consumer expects, or finishing costs required for custom coloring increase the price.
Over time, AM materials can be expected to come down in price, improve physical properties, offer more color and aesthetic options, and process faster. So why is there so much excitement about the process as a production technology?
No tooling costs - A new CAD design can be processed directly in an AM machine without any tooling: no tooling investment, no tooling qualification, and no need for outsourcing.
No tooling lead time - Injection molded plastic parts are often the gating item in the product development schedule. Removing that bottleneck (and investment risk) allows faster time-to-market for high value-add electronics and other products.
Small batch sizes - AM machines are cost-effective with batch sizes as small as one part. While larger batches may reduce individual piece prices, even a “True manufacturing batch size of one” is not prohibitive.
Design Freedom - The single most significant benefit of AM is that it decouples part complexity and cost. I’ll write a follow up on “Design for DDM” but the ability to change the design at will leads to rapid product improvement. Reducing part count can increase quality and functionality, while reducing cost.
Lean inventory - With in-house or local production of small batches, inventory costs are minimized.
Minimal waste - Manufacturers who move this production in-house have little or no packaging or shipping costs to offset.
Simplified agency compliance paperwork - If your business requires compliance with FDA GMP (Good Manufacturing Practices) or FAA or other agency documentation, making parts on an AM machine greatly simplifies documentation.