As promised during last week’s blog posting, we are talking some more about thermoforming tools produced by 3D printing.
A 3D printed thermoforming tool can take advantage of Stratasys build style to build in the vacuum channel and eliminate the need to drill out pin holes and vacuum feed areas for tooling. So you have the option of building in several ways to make the tool. Each way has some advantages but each is going to be different.
If the part needs to be fairly smooth on both the outside and inside of the shape, using a solid surface with a more traditional hole pattern where the material is drawn down by the vacuum until the tool may be the best bet. The part build style can be modified to have a spare build interior to maximize the draw (vacuum sucking the plastic sheet against the mold) while keeping the traditional solid surface. The holes can be built in by the use of the CAD program to the surface so that the need for post build finishing and drilling is minimized.
For addition, modification of the surface and fine tuning the vacuum, (as an example for areas where the sheet is difficult to be drawn into a crevice feature) the area can feature more holes in the solid surface walls. In some cases, the tool can be built with no skin so that the sheet draws down onto the open lattice surface where the part is open. This technique Is particularly useful when using a vacuum table for a quick prototype of the shape or for thin gauge applications for food packaging. The ability to pull the vacuum can be modified by using different sparse build styles and in some cases having an internal channel for vacuum channeling. There are many academic papers regarding the design of 3D printed vacuum forming tools, numerous white papers and technical bulletins that speak to design and “how to” tips when developing these tools.
Whether the choices are to create the tool with a solid surface and designed in holes, use sparse build on the interior, have a built vacuum manifold in the bottom of the tool, or to do a simple shell with holes, the possibilities of using 3D printing is endless in this application area. A couple of notes of caution, food packaging including clamshell disposable containers that are thin guage thermoforming may be subject to FDA registration rules. When In doubt on whether your application should be registered with FDA such as blister packs, thin gauge thermoforming, disposable food containers, or cosmetic packaging, always consults with experts on packaging regulations.
In general, thermoplastics sheet used for thermoforming can be used with any of the tools printed from the filaments that come from the Stratasys standard stock. For even more detail and glass smooth surfaces, PolyJet tools can be used with build in vacuum channels and pin holes.
For more information about thermoforming and how 3D printing can improve your bottom line, contact Engatech at firstname.lastname@example.org or call our offices at 866-499-7500.
Often the terms of vacuum forming and thermoforming are used interchangeably but the processes may actually be different for different professionals. In general terms, thermoforming refers to any process where the plastic is in a sheet form,is heated to soften and then placed into a mold. Thermoforming is a generic term nowadays and usually includes vacuum forming, pressure forming and twin sheet forming to form a coverall type of generic molding.
Within each process there is an incredible amount of tribal knowledge and tips and tricks; too much to cover in a blog posting. As an example, the “art” in developing a good thermoforming process may involve knowledge of snap back boxes, pre heats, female versus male molds as well a large scale sheets, draw down ratios, custom heats and more. Because of the complexity, we will stick to the basics in this blog posting today – vacuum forming and pressure forming 101. We will leave twin sheet thermoforming for a different time.
Vacuum forming is taking a sheet of thermoplastic and heating it up to soften it in preparation for molding. The softened sheet is positioned over the mold in preparation to be sucked down onto the surface of a mold. Afterwords, the formed sheet is removed from the mold, allowed to cool and then readied for further finishing. The product is trimmed and any secondary operations are completed prior to shipment.
In pressure forming, the sheet is heated and positioned the same as in vacuum forming, but a second piece of tooling (or box as some call it) with positive pressure is used in addition to the vacuum to push the sheet into the shape. Secondary trimming and additional operations are the same as in vacuum forming. The softened sheet prior to shaping may be stretched prior to the operation in order to get a better wall thickness distribution particularly in areas where the sheet will be stretched over the mold.
Each process has advantages. In vacuum forming, the pressures are lower and the overall costs of molds and set ups are usually lower. The process is ideal for larger parts and runs of less than 10,000 pieces.
Pressure forming on the other hand allows for more detail and surface texture to be added to the resulting part. Some claim that the walls are more uniform with less thinning in corners. Differences in cost are highly dependent on the processor and equipment.As far as which process is better for each part that is mostly a factor of design.
One option to consider in either process is using 3D printing to quickly produce a mold. FDM 3D printers allow you to choose your part density and by selecting a sparse style you can 3D print a prototype mold/short run mold quickly & cost effectively. This “quick to completion mold” opens up opportunities for low volume production, quick turn runs, verification of design and custom vacuum patterns for hard to draw areas in the tool.
Another aspect of using 3D printing is building a pattern for a traditional aluminum sand cast thermoforming tool. The pattern can be scaled up easily in the printer software to compensate for the shrinkage ratios as well as eliminate much of the hand work and polishing needs. With fewer skilled pattern makers working today molders need to find alternatives to patterns made from wood or resin board.
3D printing is the next stage of mold building evolution. Design moves from concept to CAD to mold directly using a 3D printer. This month we will be exploring thermoforming using 3D printing as well as blow molding tooling, but if you need to hear more NOW, we have a couple of options for you. Tune in for our webinar on June 9th at 9:00 where we will do an overview of vacuum forming and blow molding tooling done with 3D printing. You can register here: https://attendee.gotowebinar.com/register/8238370521790898948
You can also contact our offices for links to white papers, technical papers and case studies. Call 866-499-7500 or email email@example.com and we will be happy to share information about this technology with you.
Rapid Prototyping Remains the Largest Use of 3D Printing Since the 90s.
Engatech Application Engineer Barbara Arnold-Feret summarized the use of 3D printing in the 2010s as going “back to the future” but also sounded out new paths for the technology at the DFW “3D Printers and Pastries” breakfast held this morning in Grapevine TX.
She presented to a small group of industrial users of 3D printing, where she detailed that 3D printing remains the technology of choice in developing rapid prototypes of new design.
“Over 80% of all uses of 3D printing remain in rapid prototyping, where the technology is used to prove out design, fit, form and function. While we are seeing growth in tooling and end use parts, the first parts usually printed on new machines are to prove out a design or new idea.” – Barbara Arnold-Feret – Engatech
Citing new machines and materials in the market for 3D printing, she noted that the industry continues to look for faster production, stronger and more durable materials while lowering the cost of making parts via additive manufacturing. She said the recent introduction of Carbon’s and HP’s new equipment has caused speculation within the industry watchers on what the next move will be for leaders such as Stratasys.
Problem: Support material was not printing.
Background: A Connex 350 machine continued to have failed builds after cleaning, purging and troubleshooting. Examination of the machine revealed that the support materials were not being dispensed in each pass of the head, and the machine was stopping the builds.
Assessment: Troubleshooting for possible head starvation issues and clogged nozzles in the print head.
Fix: After troubleshooting and a review of configuration files, it was determined that the support heads needed to be replaced. Further questioning of the customer noted that the machine was in a hot environment where the materials and machine were regularly exposed to temperatures over 85 degrees F on a daily basis. Recommended temperatures for operation of the machine and storage of the materials noted that the storage temps should be between 15 °C and 25 °C (60 and 77 degrees F) and the room where both the machine operated and materials were stored were usually above 85 degrees F during the nights with excursions to above 95 degrees F ( 30 – 35 degrees C) on a regular basis.
Conclusions – elevated temperatures contributed to early head replacement due to materials reacting to heightened temps over a long period of time while in storage and in the machine.
A couple of my friends asked about quick tips for finishing up FDM parts so they are smooth and polished looking. I was more than happy to help, but thought that perhaps our industrial users may want an overview of some hints.
First, Stratasys sells finishing systems for FDM parts that include vapor polishing (where acetone vapor smooths the surfaces) and has a referral network to vibratory tumblers and media blasters for other types of smoothing besides sanding. Power tool sanding equipment ranges from Dremel tools to palm hand sanders, but many users complain power tools take off material far too quickly for careful finishing, so most tend to tick to hand sanding.
The parts that adapt to hand finishing best are parts that have a long area of “plain” features. For example, a part that is shaped like a cup would be ideal for hand finishing since there are not small cracks and crevices to try and dig into with a small tool to smooth out. The sides can be smoothed out and if desired, the part can be finished by painting.
First off, remove any support material that remains from the build. If the part will be painted later, you want to print in a color that is as close to your final color as possible. For example, if you intend to have a blue part, print the part using blue filament and after finishing paint in blue. You will find that your part may need little paint in those cases. Starting with your clean part use coarse grit sandpaper to knock off any obvious edges and defects and gradually move down to the fine grit sandpaper. (Start with coarse then move to fine line so – 100, 240, 400, 600, 1500, and 2000 and so on using what you have on hand.) If you have a perfectly flat surface that you are wanting to sand, a sanding block out of balsa wood keeps uneven pressure from your fingers from causing a divot on the surface. Between changes of sand paper washing or blowing off the surface with shop air will allow you to check your progress.
Once you have finished sanding and are looking for the final touches, you can polish the part with a plastic buffing compound. Note that if you are using a wheel or Dremel pressing too hard may cause heat build-up on the part surface. If you intend to paint the part, the part should be washed to remove all traces of grit, dirt or oil.
When painting the parts, make sure that the paint selected is compatible with the type of plastic you are coating. And, thin coats are much easier to control for gloss and drips than attempting to do a thick coating and short cutting the process.
On PolyJet parts, because of the superior surface finishes, you usually do not sand for finishing. On occasion, sanding is used to prep the surfaces for paint, but usually you don’t need to smooth and polish the surfaces. Ensuring the part is free of oil and dirt by washing is a good insurance policy to help assure paint adherence. Some customers prefer to paint matte surfaces and build with this finish and some gloss, but most are not painting. If you have the new J750 machine for PolyJet parts – decoration and painting is not needed – you can get the CMYK colors in and throughout the build by using our latest machine. Logos and colors can be transferred from VRML files and 3Dpdf files into the build data and the 3D printed parts look and feel like the product pieces.
Want more information on the J750 click here.
I just got my Doc Brown sunglasses for this month’s theme of “Back to the Future” and thought back to the heady days of 3D printing in the 90s. I was working as part of a service bureau making all sorts of parts and SLA and SLS widgets mixed in with other tech for good measure, and was reminded every day that I was on the cutting edge of science and manufacturing. Prototyping! Sample parts! Concept design! Having a part from CAD! Even then, the catch phrase of “This is so COOL!” followed me everywhere.
Just like the over the top publicity of 3D printing we have seen during the past 5 years, the 90s had a cycle of hype and overexposure from the media who headlined that 3D printing was going to be in every home. But in the 90s as the century ran down, most of us were looking towards manufacturing for aerospace and into space with what we could do with 3D printing. Today we are still taking on the stars with prototyping, but with ways we didn’t imagine even those short 2 decades ago.
3D printing is in space – right now printers are on the International Space Station and making parts using a FDM printer. The MIS (Made In Space) printer prints ABS in a low gravity environment to make parts, confirm that the printer can produce parts with mechanical properties, and are reliable with consistent builds. The machine has shown that additive manufacturing can be used to make the parts and tools in space, that are essential for deep space missions.
The first printed tool made in space was a ratcheting socket wrench. The wench was designed on the ground, emailed to space and then printed in orbit. If the astronauts are anything like us earthlings, the first thing they did was to take a picture and email it back to their friends and co-workers with what they made. What a great selfie!
Then today I read about the next step in space bound 3D printing. Lowe’s Innovation Lab and Made In Space sent another printer up in March that improves on the 1st printer. This printer is able to print in 3 materials including one that has an ability to withstand exposure to the outside environment in space, ABS and polyethylene. Lowes is touting the printed parts as a precursor to retail in space, but the larger picture is the ability to print on demand and save space and weight by sending a file from Earth up to the printer. The latest version of the printer also includes a scanner and more electronics so the printer can be monitored remotely, as well as standard mechanical parts. Just think – need a widget – let’s make one because the hardware store is back on Earth.
I wonder if the astronauts getting the newer model of printer are just like most of us here on Earth. Got to have the next printer model up so I can do more stuff… Need more materials… Need a bigger build area… Need more resolution…etc., etc., etc.
If you want to read more about the NASA 3D printer work and hardware, check it out here.
Many of our customers ask about using off the shelf or open source materials for their FDM machine. While there has been many open source materials come out, we always recommend that customers use Stratasys materials since there are compelling reasons for doing so.
The machine, software and materials all interface to give you the best part possible. If you use material that comes from an outside supplier, you often don’t know what the melting temperatures or the exact composition of the plastic is, and this can greatly affect your equipment and ruin your part.
For example, there are over 5000 different types of ABS. Some grades of ABS are better for injection molding, some are better for extrusion and some are better for making parts by machining. Having materials that come from Stratasys that are assured work with the FDM printer means less time that you waste and better parts.
Another factor is that material you buy off eBay or an Internet site may contain an unknown amount of recycled plastics or fillers which cause wide swings in melt temps. Added to the melt temperature swings is the risk of clogged heads or “spitting” as the material comes out due to moisture or bad materials. These problems can mean the loss of a part in mid build. In checking on social media, complaints on material problems and failed parts are widespread and cause lots of headaches for users. There are even complaints that the consistency of the build material at the beginning to the end of spool changes on some overseas supplies.
Lastly, some open source material suppliers brag that they have chips embedded in the spools so the materials will run on Stratasys machines. Using non-Stratasys material s could be even more of a problem than bad parts in these cases – users may void any service or warranty contracts plus cause errors that could interfere with machine operation. Non-Stratasys material use is a risk to your machine, parts and your business.
With all three of the things that go into making a part (hardware, software and material) in a one stop shop you have only one source to talk to regarding problems. With open source, you end up being caught in a game of finger pointing with manufacturers passing the blame to materials and vice versa. With a single source there is one place to go and the troubleshooting variables are drastically cut down.
Lastly, materials for 3D printing are an extremely small portion of plastic sales. Current figures from SPI show that in the overall plastics market, 3D printing represents less than 1% of plastic consumption. With such a small amount of plastics going towards printing, firms like Stratasys have to “mix” their formulations with specialty compounders. This means higher cost, higher quality control, and a niche market where the plastic is tailored for 3D printing. But this also means better materials, consistent builds and better results. So when you positively have get the part in the customer’s hands – the reliability and known factors of Stratasys materials makes it the best choice.
Applications for 3D printing have added up over the years, but none are more important than the first application that inspired 3D printing machines– rapid prototyping. Rapid prototyping is loosely defined as using a manufacturing method to develop a model of a part quickly prior to deploying the full production parts. In most cases, rapid prototyping uses additive manufacturing but rapid prototyping has never been exclusive to 3D printing. In fact, in the 90s, rapid prototyping commonly included the high speed machining processes and CNC work.
However, in the present day, rapid prototyping is most used in references to additive manufacturing and 3D printing. Both terms refer to using layers of material to build up into a part from 3D data. This additive technique is compared against subtractive methods of making a part where material are taken away from a block or raw shape until the part is all that is left. Because extractive techniques have inherent manufacturing limitations such as what types of shapes, hidden features and geometries, plus hard to reach spots where cutting tools may not easily reach, often the time frame and expenses of doing prototypes was skipped in favor of a “fingers crossed” 1st article of production as a proof prior to full scale up.
Unfortunately, “fingers crossed” often became “pointing fingers” when problems were discovered after a physical part was produced. In contrast, if rapid prototyping was used prior to production, the errors and guessing was eliminated. 3D printing offers a cost effective and fast method of getting a physical part produced plus the ability to do different versions prior to full production. Not only can designs be verified, the best possible design option can be selected. The pre-production parts also offered teams members such as tooling and machine shop engineers, production engineers, supervisors and design professionals a part that they could see and hold that allowed them to come together and collaborate earlier in the design process. All the aspects of planning could be accessed more easily ranging from design to how to gear up for production. With each team member holding and looking at the exact same part, this coloration tool resulted in time and cost savings plus generally less stress on all the members of the team.
One customer in aerospace for example noted rapid prototyping saved their facility over 6 months in retooling the very first time there was a change order, since the prototype could be used to plan assembly line tooling and fixtures prior to receiving a modified part. One specific instance he used was drill guides for putting in brackets – by being able to have a prototype in hand with a modified screw pattern, he could quickly put the brackets from his suppliers into the line without the trial and error and headaches from retooling that he used to suffer through.
Nowadays, time savings and collaborations are even more widespread and accepted as part of the competitive nature of business. Over 80% of all 3D printed parts are used as rapid prototypes. Some figures estimate that as much as 90% of all parts are still “prototyping” parts used to approve and collaborate on design, fit and function prior to production.
With a history of over 30 years of rapid prototyping giving great results to users, now is the time to “go back to the future” and make your mark with 3D printing! Click Here to request more information.
Engatech Notes Successful Wrestling Season for 8 Year Old Wrestler using Engatech 3D Printed Port Cover to Protect Chemo Site.
Engatech reported today that junior wrestler Colt Rowland successfully completed his season using the custom 3D printed port cover designed by Curtis Schmidt and printed by the Engatech offices using Stratasys technology. Tammy Rowland, mother of Colt, noted to Clay Slaton, Engatech’s founder and president, that the port cover made Colt’s participation in regular sports much easier.
Thank you so much. .. it could help many children with ports to be able to play sports like “regular” children. – Tammy Rowland, mother of Colt Rowland.
Colt was first diagnosed with leukemia in 2014 when he was just 6 years old and undergoes chemotherapy via his implanted chest port. Since the port area must be protected from impact and abrasion, a two part 3D printed cover made from PolyJet materials made it possible for Colt to continue to participate in team sports such as wrestling by keeping the port covered and shielded.
Using the Stratasys Connex machine’s ability to build in different materials, Engatech build the outside cushioning ring in softer Tango™ PolyJet material and the inner protective “button” covering the port area with more rigid Vero White™, Tammy Rowland reported success all around.
Engatech continues to follow Colt and his fight against cancer and his sports career.
The J750 Connex color printer announced earlier this month comes with an updated software program PolyJet Studio. Many of our users are familiar with the Objet Studio software that is bundled with the PolyJet machines, and the PolyJet Studio is an updated version that is optimized for the J750.
When we say optimized, the software includes color management as well as simplified operations. Once the part is opened in preparation for the build tray, the screen gives you the options on what colors are loaded into the “filing cabinet” which are the material docking stations. The J750 can handle 6 different build materials as well as 2 support canisters, giving the user 7 different materials to use to make their part.
The materials are automatically on the screen from what is in the loading docks, and when the part color is selected, the software will also show you the material selection against what is possible according to what is loaded into the machine. Parts that are selected for color, if different colors are to be done in different aspects of the part, should have different shells so colors can be different per area. In other words, the simple way to take advantage of all the color selections is to have a part with different shells that the entire part is then saved as an assembly into a STL file.
Here is an example of how the screen works by looking at an assembly of a foot model. The outside is clear and the bones are white.
You can see that the screen is slightly different than the Objet Studio, in that there are additional material options to select from as well as color blanket to adjust the colors selected for the shell.
The new screen also has a slightly different feel where you can easily minimize areas that you are not working with such as the tray options or the model properties.
One part of the revamped program is the color comparison area at the bottom of the model properties. On this area, you can select a color for a shell and the machine will tell you what the color will be in reality versus what you select and you can adjust.
This is an illustration.
Note the slight difference in the selected color versus the actual in the first panel. This is due to the slight gray cast of one of the Vero materials that are used in the assigned materials. But you can adjust the color selection to show a better color and it will adjust the mix. In the second case, a different base material was selected; the VeroPureWhite and the difference disappeared.
This example is just one area of the J750 and PolyJet Studio interface that a custom can use to make better, brighter, faster and more complex parts. For details, contact Engatech at 866-499-7500 or email firstname.lastname@example.org.