MDX40- Microfluidics

General discussion on ideas and applications. Things you've done, things you're considering, things you find tricky
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drehman
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Joined: Mon Feb 06, 2017 4:48 pm

MDX40- Microfluidics

Post by drehman » Thu Feb 16, 2017 2:53 pm

Dear Experts,

We in our engineering school lab are working to extend our understanding of microflows. Recently we have acquired MDX40 hoping to mill out the desired channels within our lab without having to wait for commercial channels and their associated logistics.

- Current project that we are working on is gas flow through microchannels. Due to relatively lower density of gases than liquids, generally operating pressure is high to sustain the high mass flow through the channels. In our expected work, this pressure will be around 10 bars and serious leakage issues are to be expected. We are trying to make a sandwich structure where micro-channel milled in an appropriate material (using MDX40) is sandwiched by metallic plates at top and bottom which will then be bolted altogether. Hopefully we would have this ready in coming week and I will share leakage test result with you. An illustarion explaining micro-channel assembly for gaseous microflows can be found here. https://drive.google.com/open?id=0Bwstr ... pDQm96X0FB

- Now we have milled micro-channel as a proof of concept in a 3mm plastic sheet that we had in our lab (unknown material) and will test the assembly for leakage test by maintaining it at 10bars for longer durations. A big concern is that if plastic is deformable enough then at 10bars it might bend causing leakages. Literature review has suggested to use PEEK as a milling material for microchannels (gaseous applications). PEEK seems to be tough material and therefore I wonder, would it be possible to be milled using 100W spindle of MDX40?

MDX40 Issues

1. EndMills: Only tools that we have for now are V-engraving cutters with tip diameter of 0.1-0.5mm. However with experiments, it has been observed they do not result in accurate profile reproduction when milled with MDX40. We have searched for the flat end mills in this regards and have found a local supplier as iLink (they have office in Bologna). They supply micro-mills with 0.2mm diameter (which seems quite promising to us). Only limitation is that shank diameter of all these micro tools is 4mm where MDX40 collet and spindle is 6mm (one that we have). I have searched through internet and found only America Roland store where there is only 3mm collet size is available. Is there any online store in EU where metric sized collets and associated micro tools for MDX40 can be purchased? That being said, I have found labs utilizing collets of various sizes ranging from 3mm to 6mm with their MDX40 machines (e.g. this lab:http://wiki.makespace.org/Equipment/CNC_Model_Mill see under Stock Tools header).
If such collets are not available in various metriz sizes, is it possible to manufacture them using a reference drawing of a collet (say maybe 6mm)? Anyone experienced in that? Particularly as mentioned above, we would be interested in a 4mm collet that could fit MDX6mm spindle. While asking this question, I naively believe that such collet can be used without changing the original 6mm spindle (kind of an adapter thingy!)

2. MDX40A Update: Searching alot through Roland forum, I have come to know that there is an updater to upgrade MDX40 to MDX40A. (here) Although, this updater had been downloaded and started with exe file, however it fails to recognize connected MDX40 and asks for checking the connection of MDX40 and computer. This is strange because when machine is given a priniting job from CAD software, it accepts it and perform desired cutting. While if searched by 40A updater, it fails. Can you please elaborate what is going on with our updater. We want to upgrade to 40A in order to utilize SRP player for CAM solutions.


I know its a bit too much but Thank you so much for your time and concern. Hope to have your valueable feedback and answers.

Your comments specifically to MDX40 being used for micro milling or in general for the project planning and execution are more than welcome. I will try to keep this thread up to date with ongoing activities in this regards.

Much Thanks,
Rehman

armbrusterco
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Joined: Thu Oct 20, 2016 4:41 am

Re: MDX40- Microfluidics

Post by armbrusterco » Fri Feb 24, 2017 3:13 am

You should be able to find the cutters with a 3mm or 6mm shaft.

If you can not find the cutters in the UK, here is a great supplier in the UNited States. Their products are excellent.

http://www.precisebits.com/products/car ... r-O_1F.asp

armbrusterco
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Posts: 7
Joined: Thu Oct 20, 2016 4:41 am

Re: MDX40- Microfluidics

Post by armbrusterco » Sun Feb 26, 2017 4:15 pm

Regarding your project and the need to eliminate leaks -- you may need to mill the flat surfaces of the plastic pieces to create a truly flat plane where they join together. When you clamp the two pieces together, you will want them to match face to face.

When working to get a uniform thickness on a project piece, it is a common practice to mount a sacrificial material on the table and mill the sacrificial material to a flat plane surface. Then mount your project material onto the flat surface of the sacrificial material.

I did a project with cast acrylic sheets and found that the thickness varied throughout the sheet. The variation was small and was acceptable in my project, but at the level of detail that you are working with, it may make a difference in getting a tight seal.

Bob

PhillyDee
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Re: MDX40- Microfluidics

Post by PhillyDee » Sun Feb 26, 2017 5:51 pm

Yup, the tolerance on acrylics is quite wide on cast, extruded has a far tighter tolerance, same for continuous cast (which has the best).
Roland BN-20 (CMYKWh)
Roland Versa UV LEF-20 (CMYKGlWh)
HPC Laser - LS6840PRO 60W Laser cutter/engraver
HPC Laser - LS1290PRO 80W Laser cutter/engraver
HPC Laser - LS1290PRO 150W Laser cutter/engraver
Trotec Speedy 300 120W with JC Camera system and rotary axis.

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