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Evolution of our design

Our design has evolved a lot of the past few months. We started with a 3″ pipe and plunger design and have ended up with a 1″ pipe and screw design. 

Left: The left most design in the picture above is our first design based on a melt flow index machine.  We would use a 3″ pipe as the cylinder and push the plastic through using a piston. We decided to use a pineapple during this design to help melt and mix the plastic. The initial pineapple was made from a huge threaded steel rod. It was hard to find any 3″ steel around and that was our only option.  We also had a valve in the design to turn on and off the flow of plastic. But we scrapped this later because the nozzle was not heating up.

Center: Our next design was still a piston cylinder design but with some adjustments. We actually broke the cnc mill we machined our first prototype on. We over extended the X axis and got it stuck. So this design our goal was to make the biggest piece fit within the area of the mill we would be machining everything on. The original height of the side pieces was 32″ (which is the limit we could machine), so we shortened it up by dropping the spool down and making the height of the pot lower.  This brought the height down to 28″, which was much safe for us to machine. The original had two smaller fans mounted to the side next to the nozzle. We went with one large fan located in the back. another big improvement was adding tabs to all the wooden pieces. This will help with the strength of the structure and simplicity of assembly. The first prototype is held together with wood glue and finish nails. Now we just need wood glue.

Right:  This is our current design and what our second prototype is based on.  This has the same height as the last revision but the extruder assembly is lower. This allows for the top section to be used as a hopper for plastic. The width of the side panels is an inch thinner due to the limits of the mill. The extruder assembly consist of a double threaded 1″ pipe, 2 caps, a 1″ wood auger, 12V dc motor,AL pineapple, and a nozzle. The design allows for the extruder assembly to be removes easily. This will allow the extruder Assembly to be designated to types of plastics or colors and changed out when switching plastics. A box was added to the side to house the electronics.

I am making a video to show the evolution of our design and point out the features that changed.

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We are on twitter!!

We have a Twitter page now. Follow us and stay up to date on all the little stuff @OSPrinting

Small Poll on Materials

I just wanted to see what people might be interested in the future in terms of materials.

Contact US form fixed

The form on the Contact US page has been fixed. Sorry for the inconvenience everyone. If you notice anything else wrong with the page, please let us know.

Thanks, Hackaday!

Thanks very much to our friends over at Hackaday.com for featuring us in an  awesome article. We’re big fans of the website and we’re psyched to be featured. To any visitors, feel free to poke around, and give our IndieGOGO a peek as well!

Best,

Sean

Project Spaghetti Dinner

Concept 3 built and the site going Live!!

We have finished the frame of concept 3 and it is all coming together. There are some key differences between concept 2 and concept 3. The overall frame is 6-8 inches shorter and an inch thinner. The milling machine we machined everything on had a travel range of 30″ by 10.25″. We had already over traveled it once and we did not want to chance it again. We have made a box on the side to house the electronics. The biggest change is going from a 3″ pipe to a 1″ pipe. We could not get enough pressure to force the plastic out the pipe. Also by going to a 1″ pipe we can add a screw and go to a continual feed.

A funnel was made out of a 2″ thick piece of wood that was machined down.  There are four slots drilled into each side of the pipe to funnel the plastic into the screw. The motor to the screw will be mounted to the steel cap. We are really hopeful of the potential of having the hopper in the top of the frame. The motor mounts nicely to the cap. The cap was machined down a bit inside and on top to make it flat.

We have made great progress since May when this blog started and we hope this blog helps people understand the choices we have made. The next step for us is to finish assembling the frame and mount the electronics to it. We also need to test the screw with the pellets. There is a possibility that the motor we have is not string enough but we can always get something more powerful. We have also changed our pineapple design. Since we can purchase most of the plastic pellets pre-colored. We did not need to worry about mixing. So the new pineapple will be used to ensure the plastic is melted before it gets to the nozzle.

We are also putting up plastic filament onto our Indiegogo page!!  Here is what we are offering:

1lb ABS Filament

$15.00

Whether you’re printing a Reprap to create more repraps or printing a replacement belt buckle. You need material to feed your machine. ABS plastic is used in product like legos. Choose this perk and you have the chance fuel your machine with hopes and dreams. We are offering both 3mm and 1.75mm, plus a variety of colors. Choice of colors will be done towards the end of the campaign.

1lb PLA Filament

$20.00

If you are feeling more planet friendly, than PLA is the plastic for you. It is made from corn and other renewable sources. We are offering both 3mm and 1.75mm, plus a variety of colors. Choice of colors will be done towards the end of the campaign. See the goal for PLA sales in the description.

1lb HDPE Filament

$20.00

Thats right folks, HDPE Filament is going to be hitting the shelves. HDPE is used to make milk bottles and detergent bottles. It has a melting point of 120-130 C and is not affected by water like PLA or ABS. Purchase this perk and not only are you getting high quality HDPE, but you are helping us fund the research into making and printing with HDPE. We are offering both 3mm and 1.75mm, plus a variety of colors. Choice of colors will be done towards the end of the campaign.

1kg ABS Filament

$30.00

Same as 1lb ABS Filament but even more! Color and filament size will be determined towards the end of the campaign.

1kg PLA Filament

$40.00

Same as 1lb PLA filament but even more plastic! Color and filament size will be determined towards the end of the campaign. Check out the PLA goal in the description.


We aslo have a special goal we would like to achieve.

PLA Goal

PLA has been a surprisingly hard material to acquire or find suppliers. We are lucky enough to be located in Leominster, MA, which has a good number of ABS and other petroleum based plastic suppliers in the area. When it comes to PLA we are looking for a US based supplier and one that offers good prices. We have found one supplier that will sell us 4043D PLA in smaller quantities but it is expensive. Unless we order over 1600 lbs at once. The price break is substantial and would make PLA competitive. So here is the goal for PLA sales. If we can sell over 400 lbs of PLA than we will double what your ordered. So if you ordered 1lb of PLA and we reach this goal. You will receive 2 lbs of PLA.

We are working hard to improve our process and make high quality filament. Our goal is to maintain 3mm +-.05mm. The same standard that printers demand today. Quality is the most important fact to our products and right behind it is price. We hope to bring people low cost and economical filament. People will be able to print more and create endlessly. With this great technology will come new materials. We cannot do this without your support.

Check out our Indiegogo campaign and the company website OSPrintingllc.com.

Lets change the way filament is made!!

Concept 3 First Testing

John and I met up today to work on our concept 3. The frame still needed some work, so we just tested out the 1″ pipe and the heater setup. The picture below shows the PID temp controller, 12V battery, solid state relay (SSR), 1″ pipe, heater band, and the plunger we used to push the plastic through. This was set up one a press because we were not sure what pressure everything needed to be run at. The Temperatures in the picture are in units of Fahrenheit.

The first test included the pineapple in the pipe with it press fit in. Our first test we used HDPE because the heater band we were using had trouble getting above 200 C. This would not have worked with ABS but HDPE has a melt temp of 120-130C. Once the temp got around 130 C, we filled up the pipe and pressed down on it. We noticed that a lot of force was being applied to the pipe and probably something was wrong. The test was stopped and the assembly was taken apart. The cap was difficult to get off and we found out that the pineapple had slipped down and blocked the nozzle entrance. The pineapple itself was clogged in the pipe with molten plastic around it (hey it worked though). A blow torch and a hammer solved that issue quickly.

Next test, we removed the pineapple and just used the pipe,cap, and nozzle. We hooked everything back up and proceeded to apply heat again. We kept an eye on the force gauge on top of the press. If we started to apply any kind of force, then we had to stop and let the plastic melt. The video below shows our first extruded material.

So some thing to work on for next time. The filament was brittle  because it was not heated fully and uniformly. The plastic on the outer wall was melted but the inner material was not. This will be fixed by a the pineapple. Next, we measured the filament and it came out to about .126. When the inside diameter of the nozzle is .118 (~3mm). This expansion would be due to the large amount of pressure being applied to the not fully melted plastic. Further testing will decide our course of action. Our backup plan is to machine a bolt a a nozzle. We have more control on the accuracy that way. Below is a picture of the HDPE we pulled out of the nozzle. The HDPE was easy to clean as it didn’t stick to the metal and just popped right off.  So far HDPE has been a pleasure to work with and this orange is a very nice color. It is almost a hunters orange.