CNC (Including Swiss Screw) Machining vs. Injection Molding, Which is the Right Choice?

Here is a truth every job shop knows, and sometimes customers (potential and existing) seem to forget: Quoting isn’t free. Preparing quotes is costly because it consumes the attention of knowledgeable staff members who could otherwise be giving attention (to existing) paying jobs. Customers (potential and existing) want the best pricing and delivery times they can get, economics 101, right? The belief is that sending out RFQ’s (bids), will cause job shops to yield the lowest pricing they are willing to take to “win” the RFQ, thus providing the customer (buyer) his pick of RFQ responses with the lowest pricing available. The truth is, that is not always the case. Every shop is different when it comes to employees, availability, scheduling, capability, tooling, raw material availability & delivery, machinability and of course machines themselves, thus pricing may vary greatly. However, it is a necessary process to ensure your job schedule remains booked and securing the financial future of your business. So, when CrossWind receives an RFQ, we (like everybody else I’m sure) have a process in which we go through to scrutinize each RFQ quickly, as to limit our time and resources spent on even deciding to respond to an RFQ. I should point out, that CrossWind DOES respond to EVERY RFQ that we get. However, the response may not be a bid, but rather an email or phone call stating that we are NOT bidding on the RFQ and a reason why we aren’t going to bid. Please let me explain a bit further, for any shop to bid a project, they literally must sit down visualize the entire manufacturing of a single part from start to finish. Assuming we have the capability to do the part, CrossWind takes into consideration the following when quoting: Material costs and availability Including shipping time (get quotes?) Tooling costs and availability Including shipping time (get quotes?) Setup time for machining 1 part (which is the same for 500 or 5000 parts) – this may require multiple setups depending on what delivery schedule the client is asking for. 3rd party vendors needed (heat treating, anodization, laser etching, passivation, etc.) Inc. shipping costs & process times (get quotes?) Cycle time of making 1 part (which requires working through physically machining 1 part, and then we extrapolate for each quantity tier bid) Any special handling, cleaning or assembly of each part Any special instructions (i.e. packaging) on RFQ Delivery schedule requested Qty requested (5,50,500,5000?) (R&D or Production?) Is there a middleman involved (sales rep or bidding website)? Is this just an RFQ to check their current vendor of these parts or is it possible an order will come out of it. Given these considerations, CrossWind’s RFQ process involves several people, so I want to make sure I’m not wasting valuable resources on an RFQ that we can’t even complete or meet expectations as the RFQ is requesting. I won’t bore you with the internal process to get from RFQ request to an actual quote, but just know that an accurate bid takes at least an 1-2 hours to accurately complete, once you’ve got it started. Which is at least 1-2 hours @ $0 revenue for any resources used during that time, and many times we are waiting for quotes BACK for the quotes for material, tooling, 3rd party processes, etc. So realistically, it’s 1-2 days before you get all the information together to put it in an RFQ response back to the customer. So, why am I explaining this you ask? Because I’d like our readers out there, sending out RFQ’s to multiple vendors (shops) to see that it takes time to put together an accurate quote on our end, and sometimes we may not have the time to complete the quote, or the part may not be a good fit for us to make, or we may see that we can’t make the delivery schedule you are asking for. I also want to point out that “Economies of Scale” really come into play in bidding on RFQ’s…in laymen’s terms, the higher the quantity we’re bidding the lower the pricing per part. We amortize the cost of the entire job over the quantity bid per tier. That’s why 25 parts may cost you $27/each, but 250 parts may be $10/each and 2500 parts may be $7/each. The longer we can keep your parts on the machine, they cheaper they get…job shops like CrossWind Machining don’t make any money, unless the machines are making parts! Lastly, don’t be offended if we ask you to “Price Point” the part (What are you currently paying for it?). We sometimes can tell you instantly that either we can’t beat the current price, or it will be close to what you are paying now. And it’s not worth the time and resources on our end to go through the exercise of verifying what we already knew, and not worth wasting your time waiting for an RFQ response that doesn’t do you any good. I also want to point out, that when responding to an RFQ in which we’ve never made a component, we are basing our quoted pricing on mostly estimates of some those considerations…mainly cycle time & setup time. Once we get the job, the cycle time and setup times may vary from our estimates. So, we always look at the first time making a component as a learning curve, and maybe the cycle time and/or setup time is different than our estimate. Even though we are already bid at a certain price, the NEXT time the same component is asked to be bid on we may change the pricing…either up or down. I hope this gives you some insight into what it takes on our end to figure out not only how much to quote when asked to do so, but the process and resources that go into just getting an accurate quote back to you so that CrossWind doesn’t lose money, but also we meet all of our clients specifications and delivery times needed.

As somebody who has been around machining and machine shops all my life, yet not fully understanding some of the differences between various machine types and/or their capability differences. I found a great article published by the CSI Group, that had a very good comparison that includes not only the differences between CNC (Lathes) & CNC Swiss (Lathes) Machining, but some Pro's & Con's of both. I hope that this helps you understand more of what the differences are and the capabilities are of each and why CrossWind Machining chose to exclusively use CNC Swiss Screw Machines - There are distinct advantages and applications for both CNC & CNC Swiss machines, but they are very different processes. Choosing which precision machining process depends on the specific job. Let me see if I can summarize them here for you. CNC Swiss Machining Swiss-type precision machining provides a cost-effective way to produce components for medical and defense products such as dust cover pins and firing pins used in military rifles. These long, slender components feature a tolerance band of 0.0005 inch on the part’s diameter. A Swiss-type lathe consists of a variety of turning machines that feed the stock through a guide bushing. This means the OD turning tool can always cut the stock near the bushing, and therefore, near the point of support, no matter how long the workpiece. The machine feeds the work out of the spindle and past the tool as it goes. This makes the CNC Swiss-type particularly effective for long and slender turned parts. Advantages of Swiss Turning Process The advantage of a Swiss turning process is that the material is supported close to the tools that are cutting, using a guide bushing that the bar stock is pushed thru and into the tools. This prevents deflection of the bar stock when using a conventional turning process. On many machines, the tools are only a few thousands from the face of the guide bushing. Swiss-Style Distinguishers Swiss-style screw machine, running off bar stock, typically creates a cylindrical part A 12-foot bar with automatic bar loaders in which 15-20 bars can be placed and fed through the machine The tools are machining as the bar is pushed forward through a guide bushing There are often numerous tools and multiple axes that can be used to complete the part Swiss machining can deal with complex designs and complex parts can be machined to completion on one machine Small runs from 1,000 pieces to high-volume production can be done through Swiss machining Processes can include drilling, turning, milling, boring, knurling, and many special processes Swiss turning is ideal for long parts and small-diameter parts under .125″. Examples of Swiss Parts Are: Contacts used in connectors Watch parts Shafts Long medical devices and implants A variety of connecting components for aerospace and electronics CNC Conventional Machining The first CNC precision machines were built in the 1940s and 50s and became the workhorses of the modern machine shop. Motion is controlled along multiple axes, normally at least two (X and Y), and a tool spindle that moves in the Z (depth). The position of the tool is driven by motors through a series of step-down gears, in order to provide highly accurate movements, or in modern designs, direct-drive stepper motor or servo motors. Open-loop controls work as long as the forces are kept small enough and speeds are not too great. On commercial metalworking machines, closed-loop controls are standard and required in order to provide the accuracy, speed, and repeatability demanded. Advantages of Conventional Turning Conventional turning extends the material from the chuck/collet to the overall length of the part, and then tools will move into the bar. Conventional turning is better suited for short, large-diameter parts with very tight tolerances. Conventional turning is also best suited for larger parts with difficult materials. CNC-like systems are now used for any process that can be described as a series of movements and operations. These include laser cutting, welding, friction stir welding, ultrasonic welding, flame and plasma cutting, bending, spinning, hole-punching, pinning, gluing, fabric cutting, sewing, tape and fiber placement, routing, picking and placing (PnP), and sawing. Conventional Turning Distinguishers CNC machining is ideal for forgings, castings, plates, or blocks of steel The use of higher production, special fixturing, and palletizing systems are created to facilitate the volume efficiently Tool changers in the machine store multiple tools, and the machine picks a tool for the operation, puts it back, picks the next tool and repeats the process until the product is machined to a finished state Fixtures can hold any number of parts from approximately one to 40 Examples of Conventional Turning Parts: Fluid controls Castings Automotive Anything with a diameter larger than 1.5″ I hope this sheds some light on some of the differences between conventional CNC (Lathes) & CNC Swiss (Lathes) Machining - it certainly helped me really understand which is the best to use in certain applications. Ken Smith Quality Systems Director CrossWind Machining

What the new Standard Says About Risk One particularly notable change with ISO 13485:2016 is the addition of more explicit risk management requirements. Companies will be required to consider the risk associated with a device from conception through its use. Device makers must plan and implement corrective action when problems are detected. Risk management must be incorporated into every aspect of the quality management system. "Whenever you bring expectation to the forefront, whereas you take what is implicit and make it explicit, which is really what the standard has done, then it definitely will have an impact on medical device manufacturers to reach those standards," says Alexander Crosby, Americas Program Manager-Medical Device for Intertek Business Assurance. Risk assessment has been part of this process for a long time, says Darrell Lehman, principal of DKL Solutions LLC and a former senior vice president at Intertek. "What this standard does is put it in context for the industry as well as put it in context for the supply chain and the life cycle of the product." Less is left to interpretation than in previous standards. "It extends the process of risk-based analysis as well as risk-based control and risk management and puts the onus of control on the organization that's creating the product or service," says Lehman. "That's not only just the medical device that hits the market, but it could also be a company that's providing a critical service or a critical component to that device as it goes to market." The abstract of the standard states: "The processes required by ISO 13485:2016 that are applicable to the organization, but are not performed by the organization, are the responsibility of the organization and are accounted for in the organization's quality management system by monitoring, maintaining and controlling the processes." For companies that supply goods or services to medical device companies, ISO 13485:2016 clarifies what they should be doing, and perhaps should have already been doing, to mitigate risk, says Lehman. Safety is a paramount concern. A recent white paper by BSI Group noted the following: "ISO 13485:2016 maintains the need for organizations to focus improvement activities on the continuing suitability, adequacy and effectiveness of the quality management system and the safety and performance of the medical device." The standard seems to be evolving to read closer to FDA requirements. "The way I think it is that the international standard for medical devices is harmonizing with the FDA QSR, 21 CFR Part 820 where risk assessment is something we need to think about in everything we do," says Terry Hamm, vice president of quality assurance and regulatory affairs at GW Plastics, Inc. They make a Class II device, but this might pose a particular challenge for certain types of suppliers. "If you're making components in a molding environment, you may not be accustomed to this process. It is critical to define requirements, especially, risk assessment with your suppliers," he says. The FDA recently announced they will accept audit reports from the Medical Device Single Audit Program (MDSAP) as a substitute for establishment inspection reports. The MDSAP was established to allow one regulatory body to satisfy the requirements of US FDA, Australia's Therapeutic Goods Administration, Brazil's Agencia Nacional de Vigilancia Sanitaria, Health Canada, Japan's Ministry of Health, Labour and Welfare and Pharmaceuticals and Medical Devices Agency. The MDSAP on-site report form features several entries regarding ISO 13485 compliance. Large device makers and suppliers may already manage risk in a fashion similar to what the new standard will require, says Mike Delpha, founder of Delpha Quality Consulting. However, for smaller companies with 25 to 100 employees, compliance may be more of a burden. "For them, the notion of normal risk assessment, risk analysis, when to fail, what the impact would be, how likely the impact would be, these are concepts they've never had to deal with formally," he says. Implications for Supplier Selection It can be a challenge to assess the level of risk each supplier could potentially add to your process. However, this is a critical exercise. Under the new standard, device makers are responsible for the potential risk suppliers bring to a device. Although the updates to the standard are new this year, the concept of monitoring supplier risk is hardly new. In 2008, the Global Harmonization Task Force, a group of medical device industry representatives (now the International Medical Device Regulators Forum), revised their guidance document on the control of products and services obtained from suppliers in the medical device industry. In it they state: "Failure to have any evidence on-site or provide access to any objective evidence of the controls associated with products and services from suppliers could result in the manufacturer's quality management system being non-compliant." The MDSAP on-site assessment report form has an entry for "critical suppliers" that asks for name, address and product or service of critical suppliers that provide products or services used in the audited process. Under EU regulations, quality management systems should address "resource management, including selection and control of suppliers and sub-contractors." When assessing potential suppliers, any supplier that is not aware of the new standard should be considered high risk, says Lehman. Meanwhile, suppliers who are certified to ISO 13485 themselves might be considered lower-risk. "If I was a supplier and I wanted to improve my value proposition to a group of companies, I would certainly want to be certified to this standard," says Lehman. Any supplier involved in making an implantable product should be certified, says Delpha, because of the sensitive nature of these devices. Some small suppliers may lack the resources to become certified, but even so, they cannot afford to just ignore the ISO 13485 revision. "If a small company is too burdened or does not need to do the 13485 certification, what I'm telling them to do is be able to provide evidence on request that they've done their risk analysis and risk management homework to make themselves more attractive," says Delpha. Impact on Supplier Relationships Once suppliers are selected, they must be monitored routinely. Device makers and suppliers must collaborate and communicate more than ever to make sure their risk management and quality management systems are compatible. Suppliers who support medical device may have different interpretations of how to meet the requirements of ISO 13485:2016. "One thing we've typically seen suppliers do is say, 'well, we're not producing a medical device, so how much of this applies to us?'" says Crosby. "And it does become something of a thorny question, which is, how do you apply medical device risk management if you're not ultimately producing a medical device?" Crosby encourages device makers to communicate with their clients about their role in the risk management puzzle. Be clear about how your supplier can contribute to risk mitigation and control. "The supplier over the course of time becomes somewhat educated to that and kind of understands where they sit in the ectosphere of the medical device," he says. Some suppliers may have a good handle on how the complexity of the product or service they provide contributes risk to the final medical device. However, it is difficult for suppliers to do this in a vacuum if they lack understanding of the final medical device. The more information device makers can give suppliers, the better. "We do see that to be very stovepiped," Crosby says. "That is not really an area where organizations typically work together to depict a holistic risk management picture." The 2016 revision of ISO 13485 is pushing for more continuous dialogue, monitoring and oversight. "There's opportunity for suppliers to be value-added participants in the risk management cycle." This focus on continuous feedback is new. "Historically the standards, 13485 as well as the rest, asked the company to evaluate and select suppliers and then monitor their performance and help them get better when they do, or drop them," says Delpha. However, there was not much guidance on how that process should go. Now, companies have to be more cognizant of supplier failures. Errors must be documented and managed. Some companies have been quick to step up their game. "We've gone through an evolution with supplier management," says Hamm. GW Plastics is now managing suppliers more rigorously, including audits of critical suppliers. They have three risk categories of suppliers, and they do separate risk management on each. "It's critical to clearly divide your suppliers," Hamm says. Challenges Associated with Suppliers of Services The risk associated with suppliers that provide services, rather than components, can be particularly difficult to define. For example, a supplier providing product labeling services might contribute a substantial amount of risk to the final medical device since improper labeling could result in direct patient harm. "Usually from a quality management system perspective, when we look at resources, one of the big things is understanding any individual's contributions to or the impact on quality," says Crosby. For instance, if you have hired somebody and they happen to be moving boxes from point A to point B and their impact on the medical device is low, their understanding of that context may be low. However, if those boxes happen to contain sterile, sealed medical devices whereby there is a potential for damage and thus risk to the medical device, their context needs to be higher, he says. Temporary labor is one intriguing example of a service that could potentially contribute a large degree of risk to a medical device. If you bring workers into your organization, you must ensure these individuals comply with your quality process. You can assign some of that responsibility to the firm providing workers although you are still ultimately responsible, says Lehman. "You might want to go to the contract firm and say, 'bring me people with these credentials that have already achieved this training that you're going to impart on them.'" Ideally, the supplier of temporary labor should provide context on the impact to quality and potential risk associated with the activities workers perform, says Crosby. A temporary staffing firm that trains workers would be a good choice, Hamm says, so long as his team has the chance to evaluate the training program. He would also prefer a firm with ISO 13485 certification. "If we had two comparable firms providing the same service and one was certified to ISO 13485 and one was not, we'd probably go 13485," says his colleague Sarah Brown, compliance manager at GW Plastics.15 "We're Intertek; that's part of our business is certification, so we certainly strongly believe in standards, and the application of 13485 throughout the supply chain is a good way of showing control," says Crosby. However, he adds that it is not necessarily the only way. For instance, some suppliers may have ISO standards that apply to their specialty—such as ISO 17100 for translation services.16 That can be an equivalent way of demonstrating quality control to an auditor. If a temporary labor firm had an in-house training function to educate workers on risk, FDA requirements and more, the performance of training also would demonstrate to auditors the firm is holding up its end of the risk management equation. However, certification is certainly a more explicit way of showing control than other methods. "It is a good baseline that shows an operating system," says Crosby. "You basically have shown me that your supplier understands medical device, has a quality management system and what you would need to show me is that you have given them the information that they need, information on your device or the components of your device or the service that you're providing so that they can give you back the pieces you need with quality." In an article published last year in QMed,17 Jim Ready, the manager of quality and regulatory systems at Nypro, Inc., said "A temporary labor company that holds an ISO 13485 certification demonstrates that they understand the specific quality and regulatory requirements of the medical device manufacturing environment and have made the commitment to train their temporary workforce to meet those standards." Conclusion Suppliers like CrossWind Machining that are ISO 13485:2016 certified will be well-positioned to suit the needs of device makers. Although ISO 13485:2016 certification is not the only criterion companies should use in selecting a supplier, it is certainly an important one. ISO 13485:2016 also now carries FDA compliance at the higher level than every before. Device makers are responsible for the risk their suppliers contribute to their products and certification to this standard is a signal a supplier is committed to mitigating risk. So, if you're supplies are mitigating risk at every step of the manufacturing process, it certainly limits the risk with the final medical device product. It is my opinion that only a small portion of the suppliers will follow through with the ISO 13485:2016 certification, and roll back to ISO 9000 guidelines which are NOT medical device specific (and extremely "loose"), thus leaving medical device manufacturers at a much higher risk by using those suppliers. Can you really afford that type of risk?