Implantable silicone materials can be loaded with Barium (BaSO4) for future radiological detection purposes. Both restricted (29 days or less) and unrestricted (29 days and beyond) silicone materials can be loaded with BaSO4. This allows for the silicone part to be detected in future X-Rays and CT Scans.
Typically, the silicone material is loaded with a certain percentage of BaSO4. The loading percentage will depend on the level of contrast needed for the area of the body being viewed. Another common use of Barium loading has been in clinical trials and finished devices for failure detection and assessment since a part failure may be visible. Many of the major silicone suppliers provide Barium loaded materials today in the two implantable grades of silicone. While it is most common for the unrestricted silicone materials to be loaded, some of the restricted grades are as well.
Barium loading of silicone materials is common for the following applications:
4. Toe joints
5. Markers overmolded in silicone to detect and determine placement of devices
Now it is time for some questions for discussion on Barium loading. Have you ever manufactured BaSO4 loaded silicone parts? Did you load and mix the Barium at your company or did you purchase pre-mixed Barium silicone material? What Barium loaded silicone materials did you use?
Albright Technologies can mold your Barium loaded silicone medical devices in our ISO Class 7 hard walled controlled environment room. We can also source Barium loaded silicone material for you. If you need a custom mixed material with a certain percentage of BaSO4, Albright can mix it for you. If you are in need of a quotation for a Barium silicone related project, please visit our RFQ page here.
1. Our standard turnaround is 15 business days.
2. Three, five and ten business day expedites are available when you need parts fast.
3. Injection, compression and transfer molding processes are available.
4. Albright designs and manufactures all tooling in-house for complete control.
5. We have an ISO Class 7 hard walled clean room for medical and biopharmaceutical devices.
6. We stock a massive inventory of silicones to accommodate any application.
7. Albright’s Quality Management System is ISO 13485:2003 certified by TÜV SÜD.
Last month Susan Windham-Bannister, Ph.D., President and CEO of Massachusetts Life Sciences Center, participated In the latest installment of the WBZ NewsRadio 1030 Business Breakfast series. The panelists of business leaders & experts discussed the importance of making products and profits in Massachusetts. The group also discussed how the state’s manufacturing sector is staging an epic turnaround. The event examined and discussed the stories behind manufacturing success and how the state is helping to foster this growth and the beneficial ripple effect it is creating for the Commonwealth and beyond.
Click here to watch the video of the Business Breakfast.
Click here to learn more about Massachusetts Life Sciences Center.
Article From: Modern Machine Shop, Derek Korn, Senior Editor
Albright Technologies has become adept at micromachining molds for silicone parts such as the one to the right. This has enabled the company to become effective in quickly generating prototypes for medical device manufacturers pressured to speed new products to market. Many of the silicone components it creates are either tiny themselves or have miniscule features measuring just a few thousands of an inch. What’s interesting is that the company has found it can produce prototypes faster by taking a slower, more conservative approach to micromachining molds using end mills that measure just a few thousands of an inch in diameter.
Plus, while one might assume that very high spindle speeds are needed to effectively mill molds using such small tools, the machine that performs micromachining at Albright—a 30-taper VMC—typically spins 0.005-inch-diameter tools at just 9,000 rpm. Although that means feed rates and cycle times are relatively slow, there are a number of reasons why a company focused on quickly turning prototyping work finds this acceptable. David Comeau, Albright’s president, and Robert Waitt, vice president, explained why during a recent visit to the New England-area molder.
Click here to read the rest of the article.
Question: I’d like to know more about implantable medical silicone.
Answer: Implantable medical silicone has the capability of being implanted in a living body without the risk of rejection. Commonly, the implantable medical silicone is categorized into two types: short term (restricted) and long term (unrestricted) implantable silicone.
The short term implantable medical silicone is used for a temporary medical application – normally ranging from 1 to 29 days. For example, a suture sleeve is made of short term implantable silicone to hold parts of a medical device to keep them in place during a suture. Once the suture is done, the suture sleeve is removed from the patient’s body. The long term implantable silicone should be able to remain inside the patient’s body for 30 days or more. A good example of long term implant application is the Left Ventricular Assist Device; this device helps the patient maintain the pumping ability of a heart that can’t sufficiently pump blood throughout the body on its own. This device isn’t removed until the patient has a donor.
Each medical silicone implant application requires certain implantable silicone. A medical device containing implantable medical silicone or other biomaterials must be carefully evaluated according to ISO 10993 before it is implanted into a patient’s body; the ISO 10993 contains a series of standards for evaluating the biocompatibility of the device. Also, it sometimes is tested according to ASTM (American Society for Testing and Materials) depending on individual application.
There are commercially implantable medical silicone materials available in high consistency silicone rubber (HCR) and liquid silicone rubber (LSR). Color additives can be added to meet the requirement of a medical application, but it is recommended that the color additives should have the same class and manufacture as the implantable silicone to prevent defects. The implantable medical silicone can also be mixed with additives such as tungsten and barium that allows the implants to be viewed easily with medical imaging equipment.
Therefore, selecting an implantable medical silicone for a medical device should be thoroughly evaluated prior to implantation. If you have any other questions, please email Phayhean Soo directly at firstname.lastname@example.org.
Question: With all the new options today, could you please tell me what is the best and least expensive way to prototype a part (about 3″ x 2″ x 2″) made in Liquid Medical Silicone Rubber?
Answer: For low volume prototyping of medical silicone parts your best option is typically to create a single cavity aluminum (faster and cheaper than steel) compression or transfer molding tool. While others may swear by jumping straight into an injection molding tool, it could take a machinist and technician longer to set up and process a liquid silicone injection molding tool than it would to make 25 parts in a compression mold.
If cost is your most critical concern, and your target first run of medical silicone volume is extremely low, you may also wish to look into getting an acrylic mold made (instead of aluminum). The costs of fabricating an acrylic mold is significantly less than a metal mold. But be forewarned, if you purchase an acrylic tool, you will likely be stuck running an RTV (Room Temperature Vulcanization) material (so your cycle times will be long), you won’t be able to put any real pressure on it (so your dimensions could vary significantly), and your mold is going to wear out FAST. You might only get 10 parts out of an acrylic tool, vs. 10,000 out of an aluminum tool, and 100,000 out of a steel tool.
While many can be seduced by the $500 – $1,000 price tag on an acrylic mold, it might take 10 of them to make 100 parts, at this point, an aluminum tool would already have been paid for, and well into a small scale production run. It is for this reason that Albright Technologies does not fabricate acrylic molds.
If you have any other questions, please email Kevin Franzino directly at email@example.com.
Question: In your prototyping experience, are you capable of over-molding medical liquid silicone onto thermoplastic materials? If so, what is the lowest melt temperature material that you have been successful without deforming the substrate (ABS, Nylon, Polycarbonate, etc.)? Additionally, do you find that a silicone primer is always necessary when over-molding?
Answer: In our experience, we have had success bonding medical silicone with certain thermoplastic materials. Since different types of materials require different temperatures to work with, it would solely depend on that specific material. Over-molding medical silicone to plastics is limited to either using low temperature or faster cycle time. Plastic substrates would not deform under low temperature, but it will increase the cycle time during the over-molding process. In contrast, using high temperatures can lower the cycle time, but can potentially damage the plastic substrate. Using silicone primer helps the over-molding process, there are some other options available such as adhesive grade medical silicone and surface treatments.
If you have any questions please feel free to post a comment or email me directly at firstname.lastname@example.org.
Question: In your prototyping experience, are you capable of over-molding onto thermoplastic materials? If so, what is the lowest melt temperature material that you have been successful without deforming the substrate (ABS, Nylon, Polycarbonate, etc.)? Additionally, do you find that a silicone primer is always necessary when over-molding?
Answer: In our experience, we have had success bonding silicone with certain thermoplastic materials. Since different types of materials require different temperature to work with, it would solely depend on that specific material. Over-molding silicone to plastics is limited to either using low temperature or faster cycle time. Plastic substrates would not deform under low temperature, but it will increase the cycle time during the over-molding process. In contrast, using high temperature can lower the cycle time, but can potentially damage the plastic substrate. Using silicone primer helps the over-molding process, while there are some other options available such as adhesive grade silicone and surface treatments.
If you have any questions please feel free to post a comment or email me directly at email@example.com.
Question: I am developing a new silicone part design which requires two different hardness levels on a single silicone part. Is there any kind of restriction and/or special requirement to over-mold a lower level of hardness silicone over another one?
Answer: There is no standard requirement for molding one silicone to another but points to consider: The softer silicones deflect more easily risking increased variance between parts and/or part failure. Silicone to silicone bonding in same series materials is often easier to predict than materials in different series or from different manufacturers. Two major considerations are holding and shutoff. The first shot part needs to be located and held in a mold while the over molding is done. Shutoff offs control the transition line between the two materials and directly relate to the geometry of the final part and all its components.