医疗器械的使用3D印刷模具的液体注射成型快速，低成本原型
Summary
我们已通过使用用于模具的设计和改进的干燥器熔融沉积建模三维打印机作为液体喷射系统设计了一种方法用于低成本和液态弹性体橡胶注射成型设备的快速原型。
Abstract
生物惰性的弹性体，如硅树脂是用于医疗装置的制造有利的材料，但形成和使用传统的液体注射成型工艺的固化这些弹性体可以是一个昂贵的过程中，由于模具和设备的成本。作为一个结果，它在传统上一直不切实际的使用液体注射成型的低成本，快速原型应用程序。我们已经发明了一种方法，用于快速和低成本的生产液态弹性体的注塑装置，它利用进行模具设计和修饰的干燥器作为注射系统熔融沉积建模三维打印机。成本低，在这种技术的快速周转时间降低门槛迭代设计和原型制作复杂的弹性体装置。此外，在这个过程中开发的CAD模型可以购买适合于金属模具的模具设计，从而实现了容易过渡到一个传统的注塑成型工艺。我们已经用这种技术制造intravagINAL探头涉及复杂的几何形状，以及包覆成型在金属部件，使用中的学术研究实验室常用的工具。然而，这种技术可以很容易地适应创建许多其他应用的液体注射成型设备。
Introduction
液体注射成型（LIM）（也称为反应注射成型）经常被用来制造从热固性弹性体的弹性装置，但高工装和设备成本需要大量的前期资本投资1。此外，LIM可以在技术上具有挑战性的和昂贵的实现与复杂的几何形状和包覆成型要求的情况。其结果是，它通常是不切实际的，使用传统的LIM在超低量或与早期设备的设计，往往招致迭代修改。
典型的流程型注塑弹性体材料包括注射液单体在大约150磅的压力注入模具使用专门的成型机械2。的温度和压力进行控制，以确保层流，并防止空气被截留在模具3。原料通常是由两部分组成的硫化体系，如铂固化有机硅，叔帽子是在注射之前保存在单独的温度和控制室。原材料的两个组件被泵入高压混合室，其随后送入模腔。固化是通过在催化剂的存在下以及温度约150-200℃4来实现。模具加工通常由钢或铝，公差精确到周围建立离别边缘3,5良好的密封。不幸的是，这个过程一般比较适合于较大规模的生产给予了高度的模具加工成本以及专门的注入和反馈控制系统的要求。
对于聚氨酯（PU）份的快速原型设计，它有可能使用立体光刻（SLA）来创建一个主模和生产硅橡胶模具6,7。然而，这种技术不适合于包覆成型，因为它是难以实现的包覆成型的部件的精确对准，因为硅酮是，由设计，而不是一个刚性结构。此外，生产具有复杂几何形状，如内陷或挖空部分的设备，是困难或不可能。对于复杂或精密模具分型线和刚性薄元素的要求是，往往不是，用液体橡胶成型工艺不兼容。
上述生产规模或后期成型过程往往是不切实际的早期医疗设备开发一些设备需要制作了验证性的概念和可行性在人类研究中，这是常有的情况下，在学术实验室和初创公司的环境。替代品的缺乏常常意味着即使是早期发展会产生高昂的成本，需要许多设备开发，限制设备的功能或将开发搁置，而额外的资金募集。这有助于在开发过程中，因为医疗设备重新很大一部分急剧减速 QUIRE实现复杂的功能。这也是困难的，因为概念证明型的数据往往是尚未建立，以应付该等设备的昂贵的开发。我们在本实验中最近的一个项目，涉及硅阴道探头的发展，模制电和光学传感器，需要一个杯状尖，以符合指定的宫颈几何遇到了这个障碍。在这篇文章中描述的过程记录我们试图规避这种恶性循环，并迅速达到证明型概念LIM医疗设备。
在图1中所示的技术解构LIM过程分成5个主要的活动：（1）模具的设计和生产，（2）模具组件（3）弹性体混合，（4）弹性体注射剂，和（5）弹性体的固化和脱模。
PG“宽度=”600“/>
（1A）创建模具使用计算机辅助设计工具，（1B）的3D打印模件，（2）组装使用螺纹杆和螺丝模件，（：。协议，其中涉及图1协议概述概述3）混合液态弹性体和装入注射器中，（4）注入液体弹性体进入模具用改进的干燥器，（5a）中固化所述弹性体在温度可控的烤箱，和（5b）从脱模固化的弹性体装置模件。
模具设计涉及到计算机辅助设计（CAD）软件，从模具分型线的固体块和定义的模具师傅的减法开发一个模具师傅的。模件被创建，然后组装用螺钉，杆，和锁紧螺母定位在模腔中包覆成型的部件。弹性体混入克包括部分相结合的原料和脱气和B以消除潜在的空隙的材料。接着，弹性体注射涉及模腔的压力驱动的填充，随后弹性体固化的温度控制烘箱中，以确保该聚合物链的化学交联。
打破注塑过程分为以下步骤使我们能够放弃传统的LIM设备支持的低成本替代品。例如，而不是机加工的金属模或铸件从模具主人的硅橡胶模具，从在这个手稿中描述的协议建立的模具是从丙烯腈 – 丁二烯 – 苯乙烯（ABS），使用熔融沉积成型（FDM），三维创建塑料打印机8,9。相较于建筑金属模具或模具的SLA，FDM通常是一个更便宜和更快的过程。相当复杂的模具可迅速被印刷在一个内部的三维打印机，或由许多合同三维内印刷的一个廉价地生产提供3G业务。例如，一个复杂的八件3D印刷模具用于铸造的证明阴道探头在有代表性的结果部分， 如图14和图15所示。所有部件该模具可以打印在大约1.5天一个内部的三维打印机。周转时间为更简单的模具可以是几个小时。必要的时候以原形使用FDM的3D打印机打造模具设备的总长度是类似投出的模具硅橡胶，并创建一个聚氨酯原型所需的时间。然而，使用FDM三维打印机创建模具使得不能容易地使用有机硅模具完成几件事情：（1）许多热固性弹性体可用于所提供的三维印刷模具可以容忍所需的固化温度，（2）复杂的几何形状可以使用许多不同的模件和分型线被创建，以及（3）使用刚性模件允许精确和reproduci在模腔中的OM组件竹叶提取对齐。
而不是使用传统的LIM机，它结合了混合，注射，和固化的，有可能用一个实验室混合器，以确保均匀混合，注射用的改性干燥器，和一个标准的温度控制烘箱中进行固化。注射系统使用现成的搁板组件创建并涉及增加了一个正压力供给线到连接到填充有混合的弹性体的注射器从干燥器中。在台式干燥器室加压通常是由腔室中，真空供给线路，和大气之间的三通阀控制。修改后的干燥器以及正压供给线输送到注射器柱塞的背面。这使得能够创建一个40-50 psi的压力差足以用于液体材料注射到模腔中。
这种技术允许我们机生产线CE硅胶阴道探头，模制电和光学传感器来收集证明了概念数据的I期临床试验。硅酮被选中是因为需要对生物惰性以及消毒用多种方法10,11的能力。此外，该装置需要复杂的和非传统的杯形几何的探针，其中传感器位于与子宫颈的接口的前端。在不使用所描述的技术的，这将是一个更加昂贵和漫长的过程，以产生这些设备。相比于传统的LIM过程，使得它的实际采取快速和迭代方法来设计的弹性装置的LIM过程的这种适应降低了成本和设备的需求。
Protocol
Representative Results
Discussion
所有上述步骤，仔细模具设计是最关键的成功之路。模具主机应该被创建为一个实心体与外部几何形状应使其在最终的设备。这些几何形状应调整，以考虑任何材料收缩率，由于所选择的弹性体以及3D打印机的分辨率和公差。模具分型线和通孔的螺纹杆和螺钉的位置是依赖于彼此。加的分型线增加线性和旋转度模装置自由的编号。贯通孔和螺纹杆和螺丝作用来限制这些相同自由度。模具必须被设?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
The authors thank Sungwon Lim for intellectual contributions to device and mold design as well as Jambu Jambulingam and Rebecca Grossman-Kahn for creating intravaginal silicone probes using this process. This work is supported by the Bill and Melinda Gates Foundation, the Vodafone Americas Foundation, and the FDA (2P50FD003793).
Materials
| ABS Model Material | Stratasys | P430 | Model Material for uPrint Plus SE (Step: Mold Design & Production) |
| Soluble Support Material | Stratasys | SR-30 | Support Material for uPrint Plus SE (Step: Mold Design & Production) |
| Underwater Silicone Sealant, 2.8 Oz Tube, Clear | McMaster-Carr Supply Company | 7327A21 | Silicone RTV for sealing gaps at mold parting lines (Step: Mold Assembly) |
| Tubing, 1/8" ID, 1/4" OD, 1/16" Wall Thickness, Ultra-chemical-resistant Tygon PVC, Clear | McMaster-Carr Supply Company | 5046K11 | Forms runner/sprue adapter between mold and syringe with elastomer (Step: Elastomer Mixing) |
| Coupling, Adapter, Straight, Male Quick-turn (Luer lock) X 1/8" Tube Barb, Nylon | McMaster-Carr Supply Company | 51525K123 | Connect runner/sprue between mold and syringe with elastomer (Step: Elastomer Mixing) |
| Coupling, Adapter, Staight, Female Quick-turn (Luer lock) X 1/8" Tube Barb, Nylon | McMaster-Carr Supply Company | 51525K213 | Connect runner/sprue between mold and syringe with elastomer (Step: Elastomer Mixing) |
| Cap, Female Quick-turn (Luer lock), Nylon | McMaster-Carr Supply Company | 51525K315 | Cap to prevent silicone from leaking out of mold after injection (Step: Elastomer Mixing) |
| Liquid Silicone Rubber (LSR) 30 – 10:1, Implant Grade | Applied Silicone Corporation | PN40029 | Substitute with the elastomer of your choice. This is the one used for the intravaginal probe (Step: Elastomer Mixing) |
| Syringes (BD), 1mL Slip-Tip, non-sterile clean, bulk | Cole-Parmer | WU-07945-00 | Syringes for transfering elastomer material (Step: Elastomer Mixing) |
| Syringes (BD), 1mL Slip-Tip, non-sterile clean, bulk | Cole-Parmer | WU-07945-04 | Syringes for transfering elastomer material (Step: Elastomer Mixing) |
| Syringe, 20mL, Open Bore, Solid Ring Plunger and Grip | Qosina Corporation | C1200 | Syringes for transfering elastomer material. Open bore is used for very viscous elastomers. (Step: Elastomer Mixing) |
| Needle (BD), Non-sterile Clean with Shields, 18 gauge X 1.5" Lg., Stainless Steel, BD Bulk | Cole-Parmer | WU-07945-76 | Used for removing air column between syringe plunger and elastomer (Step: Elastomer Mixing) |
| Plastic Cups, 12 Oz., Clear | Safeway | N/A | Used for mixing silicone in THINKY Mixer (Step: Elastomer Mixing) |
| Polyethylene Bag, Open-Top, Flat, 5" Width X 6" Height, 2-MIL Thk. | McMaster-Carr Supply Company | 1928T68 | Used for mixing silicone in THINKY Mixer (Step: Elastomer Mixing) |
| Rubber Band, Latex Free, Orange, Size 64, 3-1/2" L X 1/4" W | McMaster-Carr Supply Company | 12205T96 | Used for mixing silicone in THINKY Mixer (Step: Elastomer Mixing) |
| Parafilm Wrap, 4"W | Cole-Parmer | EW-06720-40 | Used for mixing silicone in THINKY Mixer (Step: Elastomer Mixing) |
| Syringe Barrels with Stoppers, Luer Lock, Air Operated, 50mL | EWD Solutions | JEN-JG50A-15 | Smaller syringes can be used if less elastomer is required, but make sure it is compatible with Air Operated Syringe Adapter in injection chamber (Step: Elastomer Mixing) |
| Sealant Tape, Pipe Thread, 50'Lg X 1/4" W, .0028" Thk, 0.5 G/CC Specific Gravity | McMaster-Carr Supply Company | 4591K11 | Teflon Tape for air-tight seals around at threads (Step: Elastomer Injection) |
| Scalpel Blades, Disposable, No. 22 | VWR | 21909-646 | Used for cutting tubing and demolding (Step: Curing & Demolding) |
| Kimwipes | VWR | 21903-005 | (Step: Curing & Demolding) |
| 2-Propanol, J. T. Baker | VWR | JT9334-3 | (Step: Curing & Demolding) |
| uPrint Plus SE 3D Printer | Stratasys | uPrint Plus SE | Other 3D printers can be used (Step: Mold Design & Production) |
| Screw, Cap, Hex Head, 1/4"-28 , 2-1/2" Lg, 18-8 Stainless Steel | McMaster-Carr Supply Company | 92198A115 | Screws used with nuts to compress mold (Step: Mold Assembly) |
| Nut, Hex, 1/4"-28, 7/16" Wd, 7/32" Height, 18-8 Stainless Steel | McMaster-Carr Supply Company | 91845A105 | Screws used with nuts to compress mold (Step: Mold Assembly) |
| Stud, Fully Threaded, 1/4"-28, 1" Lg, 18-8 Stainless Steel | McMaster-Carr Supply Company | 95412A567 | Threaded-rods can be cut to desired length and are used with nutes to compress mold (Step: Mold Assembly) |
| Planetary Centrifugal Mixer | THINKY USA Inc. | ARE-310 | Mixers are strongly recommended for fine mixing and to reduce degassing time, but hand mixing is fine (Step: Elastomer Mixing) |
| Laboratory Weigh Scale | Mettler-Toledo International Inc. | EL602 | (Step: Elastomer Mixing) |
| Desiccant Vacuum Canister, Reusable, 10-3/4" OD | McMaster-Carr Supply Company | 2204K7 | This desiccator is used for degassing the elastomer (Step: Elastomer Mixing) |
| Custom 3D-Printed Mixer-to-Cup Adapter | N/A | N/A | Modeled in Solidworks CAD and 3D printed (Step: Elastomer Mixing) |
| Tubing, Smooth Bore, 1/4" ID, 1/2" OD, 1/8" Wall Thickness, High Purity Tygon PVC, Clear | McMaster-Carr Supply Company | 5624K51 | Tubing outside of Desiccator (Step: Elastomer Injection) |
| Tubing, Smooth Bore, 3/8" ID, 5/8" OD, 1/8" Wall Thickness, High Purity Tygon PVC, Clear | McMaster-Carr Supply Company | 5624K52 | Tubing to adapt to Air/Vacuum Supply (Step: Elastomer Injection) |
| Coupling, Reducer, Straight, Vacuum Barb 3/8" Tube ID X Vacuum Barb 1/4" Tube ID, Brass | McMaster-Carr Supply Company | 44555K188 | Adapt Tubing outside Desiccator to Tubing leading to Air/Vacuum Supply (Step: Elastomer Injection) |
| Clamp, Hose & Tube, Worm-Drive, for 7/32" to 5/8" OD tube, 5/16" Wd., 316 SS | McMaster-Carr Supply Company | 5011T141 | Used on tubing to create Air/Vacuum-tight seal at junctions (Step: Elastomer Injection) |
| Clamp, Hose, Smooth-Band Worm-Drive, for 1/2" to 3/4" OD tube, 3/8" Wd., 304 SS | McMaster-Carr Supply Company | 5574K13 | Used on tubing to create Air/Vacuum-tight seal at junctions (Step: Elastomer Injection) |
| Coupling, Tee, Vacuum Barb 1/4" Tube ID, Brass | McMaster-Carr Supply Company | 44555K138 | Tee Junction between Vacuum, Three-way T-valve on Desiccator, and Three-way L-valve (Step: Elastomer Injection) |
| Coupling, Tee, 1/4 NPT Female X Female X Male, Brass | McMaster-Carr Supply Company | 50785K222 | Tee Junction between Pressure Gauge, Chamber, and Three-way L-valve (Step: Elastomer Injection) |
| Valve, Ball, Straight, T-Handle, 1/4 NPT Female X Male, Brass | McMaster-Carr Supply Company | 4082T42 | Three-way L-valve (Step: Elastomer Injection) |
| Coupling, Adapter, Straight, Vacuum Barb 1/4" ID Tube X 1/4 NPT Male, Brass | McMaster-Carr Supply Company | 44555K132 | Adapter for Three-way L-valve-to-Tubing (Step: Elastomer Injection) |
| Saw, Hole, Bimetal. 1-3/8" OD, 1-1/2" Cutting Depth | McMaster-Carr Supply Company | 4066A25 | Used to cut holes in Desiccator for throughwall fittings (Step: Elastomer Injection) |
| Arbor, 9/16" to 1-3/16" Saw, 1/4" Hex | McMaster-Carr Supply Company | 4066A76 | Used to cut holes in Desiccator for throughwall fittings (Step: Elastomer Injection) |
| Arbor Adapter for 1-1/4" Thru 6" Dia Hole Saws | McMaster-Carr Supply Company | 4066A77 | Used to cut holes in Desiccator for throughwall fittings (Step: Elastomer Injection) |
| Coupling, Straight, Through-Wall, 1/2 NPT Female, Polypropylene | McMaster-Carr Supply Company | 36895K141 | Throughwall fittings leading to Pressure/Vacuum Gauges (Step: Elastomer Injection) |
| Coupling, Adapter, Straight, Reducing, Bushing, Hex, 1/2 NPT Male X 1/4 NPT Female, Brass | McMaster-Carr Supply Company | 4429K422 | Reducing tube diameter inside the Desiccator to adapt to Air-operated Syringe System (Step: Elastomer Injection) |
| Coupling, Adapter, Straight, Reducing, Bushing, Hex, 1/4 NPT Male X 1/8 NPT Female, Brass | McMaster-Carr Supply Company | 4757T91 | Reducing tube diameter inside the Desiccator to adapt to Air-operated Syringe System (Step: Elastomer Injection) |
| Coupling, Adapter, Straight, Vacuum Barb 1/4" ID Tube X 1/8 NPT Female, Brass | McMaster-Carr Supply Company | 44555K124 | Reducing tube diameter inside the Desiccator to adapt to Air-operated Syringe System (Step: Elastomer Injection) |
| Syringe Adapters, Air Operated, 30/50mL | EWD Solutions | JEN-JG30A-X6 | Air operated syringe adapter on the inside of the Desiccator; must be compatible with syringes used to hold elastomer (Step: Elastomer Injection) |
| Gauge, Dual-Scale Vacuum, 2-1/2" Dial, 1/4 NPT Male, Bottom Connector, 30" Hg-0, Steel Case | McMaster-Carr Supply Company | 4002K11 | Vacuum Gauge (Step: Elastomer Injection) |
| Gauge, Dual-Scale Vacuum and Compound, 3-1/2" Dial, 1/4 NPT Male, Center Back, 30" Hg-0, 100 PSI, Steel Case | McMaster-Carr Supply Company | 4004K616 | Pressure Gauge leading to Air-operated Syringe System (Step: Elastomer Injection) |
| Oven, Vacuum, Isotemp, Economy | Fisher Scientific | 280A | Standard non-vacuum oven can be used (Step: Curing & Demolding) |
| Solidworks CAD | Dassault Systèmes | Solidworks Research Subscription | Other CAD Software can be used for mold master and mold design (Step: Mold Design & Production) |
References
- Painter, P. C., Coleman, M. M. . Essentials of Polymer Science and Engineering. DEStech Publications. , (2009).
- Rosato, D. V., Rosato, M. G., Schott, N. R. Reaction Injection Molding. Plastics Technology Handbook – Volume. 2, 103-139 (2010).
- Cybulski, E. . Plastic Conversion Process: A Concise and Applied Guide. , (2009).
- Ortiz, H. e. r. n. &. #. 2. 2. 5. ;. n. d. e. z., J, T., Osswald, Modeling processing of silicone rubber: Liquid versus hard silicone rubbers. Journal of Applied Polymer Science. 119, 10-1002 (2010).
- Dym, J. B. Injection Molds and Molding: A Practical Manual. , (1987).
- Mueller, T. Stereolithography-based prototyping: case histories of applications in product development. Northcon 95. IEEE Technical Applications Conference and Workshops Northcon. , 305–310, doi:10.1109/NORTHC.1995.485087. , (1995).
- Hilton, P. . Rapid Tooling: Technologies and Industrial Applications., 288, Press: Boca. , (2000).
- Ahn, S. -. H., Montero, M., Odell, D., Roundy, S., Wright, P. K. Anisotropic material properties of fused deposition modeling ABS. Rapid Prototyping Journal. 8 (4), 248-257 (2002).
- Cheah, C. M., Tan, L. H., Feng, C., Lee, C. W., Chua, C. K. Rapid investment casting: direct and indirect approaches via fused deposition modelling. The International Journal of Advanced Manufacturing Technology. 23 (1-2), 1-2 (2004).
- Harris, A., Wild, P., Stopak, D. Silicone Rubber Substrata: A New Wrinkle in the Study of Cell Locomotion. Science. 208 (4440), (1980).
- Moisan, M., Barbeau, J., Moreau, S., Pelletier, J., Tabrizian, M., Yahia, L. H. Low-temperature sterilization using gas plasmas: a review of the experiments and an analysis of the inactivation mechanisms. International journal of pharmaceutics. (1-2), 226-221 (2001).
- Etemadi, M., Chung, P., Heller, J., Liu, J., Rand, L., Roy, S. Towards BirthAlert – A Clinical Device Intended for Early Preterm Birth Detection. IEEE Trans Biomed Eng. 10, (2013).
- Etemadi, M., Chung, P., et al. Novel device to trend impedance and fluorescence of the cervix for preterm birth detection. Conf Proc IEEE Eng Med Biol Soc. 2013, 176–9, doi:10.1109/EMBC.2013.6609466. , (2013).
- Owen, S. R., Harper, J. F. Mechanical, microscopical and fire retardant studies of ABS polymers. Polymer Degradation and Stability. 64, 449-455 (1999).
- Cassidy, P. E., Mores, M., Kerwick, D. J., Koeck, D. J., Verschoor, K. L., White, D. F. Chemical Resistance of Geosynthetic Materials. Geotextiles and Geomembranes. 11, 61-98 (1992).
- Akay, M., Ozden, S. The influence of residual stresses on the mechanical and thermal properties of injection moulded ABS copolymer. Journal of Materials Science. 30 (13), (1995).
