Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CAD - Page 2

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Thread: Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CAD

  1. #21
    Member peteeng's Avatar
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    Default Re: Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CA

    Hi William - Remember to publish the Scope here. So by now you will have a lot of stuff floating around in your head and the ToDo list will be quite big. A warning... A machine has to have a purpose. If it doesn't then it sits in a corner corroding away loosing value and enthusiasm. If you build a big machine and only do small parts then you have wasted floor space and $$$ and you will wear the machine preferentially and you will kick yourself for having such a big machine to do little jobs. You have stated that its a GP mill. There are lots of commercial mills out there new and second hand that could do your stuff. You are about to spend a lot of time and effort and money on something that will have little resale value.

    This is why I suggest you look at cloth cutters or a specialised machine that fulfills some external need. If you want this machine to make money then it has to have a client and a purpose. If it's just for hobby use then downsize it as a technology tester/prototype. A 300x300 milll will get a lot of stuff done and be significantly cheaper then the 400x600 spec at the moment. You should be near a tipping point from research to doing something soon. Now's the time to contemplate the bigger picture of where this machine sits.

    Projects sit within projects, within projects, within projects. If you want a sponsor the machine has to sit within their picture which will be bigger then your picture. To get something to happen you need to frame the project within the bigger stuff. Then if the bigger project moves your project moves effortlessly. If your project is contained and personal its limited to your personal resources... and will stall. Peter



  2. #22
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    Default Re: Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CA

    Hi Wiiliam and others - Epoxy Granite

    read here - start at page 122
    https://www.cnczone.com/forums/epoxy...frame-124.html

    I've attached a suitable resin. Cheers Peter S

    Attached Files Attached Files


  3. #23

    Default Re: Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CA

    Thank you Peter, I have lots of stuff to think about. You're right I don't have to select a material, I can simply make a few comparisons and designs which eventually will point towards the best materials to use. I did tinker around with some shape optimization yesterday for the first time in my life. Pretty interesting stuff, I still need to learn a couple of things about it.

    4) Yes good idea I'll just use C7 ball screws for WillMill Junior.
    5) I got a quote from a manufacture in China that are willing to send me carbon fiber cutoffs for $24.5/kg so that's good to know. That's still a lot of money so now I will have to figure out just how much weight I can save by adding carbon to the composite. I'll probably end up adding carbon where it's most needed and then use a cheaper kind of fiber for other areas.

    8) Yes this is turning towards a one off machine, this will definitely be a unique and interesting machine

    - Yes please don't stop chucking interesting process, materials and good ideas towards me. More data in --> better chance of superb designs as outcome.

    Do you have any pictures of your first xyz gantry robot? - I'd love to see it!

    I'll be working on writing down the scope of the project today so that I can get a design/build log up and running where people can follow the progress of the project.
    Stabilizing wood with epoxy, what a genius idea! I'm so happy that you mentioned this, as I can apply this this process for a product I intend to make in the future. This really really makes the production easier and will increase my products quality, what a great thing.

    Regards William

    Last edited by Williamlii; 04-21-2020 at 10:25 AM.


  4. #24
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    Default Re: Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CA

    Hi William - With materials just find sources and costs. Especially free stuff (swarf, CF offcuts, sawdust, sand from the beach?)Then you can put that puzzle together soon. I think the short fibre supplier in France will be cheaper. I don't think I have photos of that job, so long ago and so many other machines since. Wood is mainly cellulose which has a density of 1500kg/m3. So your plywood is say 750kg/m3 is half air. Balsa is 3/4 air. Timber (or wood depends on your upbringing) in a tree is cellulose straws bundled together to make a structural member that transports water. So when you stabilise with epoxy or PMMA which has a density of ~1100kg.m3 you more or less double the density of the wood. So if your product is weight sensitive be careful with how dense you make the wood!!

    The best thing about using PMMA (Cactus juice) is that it is very thin and does not have a gel time. Once infused you can put it in an oven at 90C and it cures. Pour the rest back into the tin. Maybe cactus juice is the go for the machine parts.... we shall see.... I have infused many wood things for various reasons. If there is a cabinet maker nearby that makes lots of sawdust its a great filler and again its free...Peter

    please not that wood and sawdust have a lot of moisture in it and requires vacuum drying prior to infusion. Only takes a little bit of water to run the job... same applies to the machine parts they will require a vacuum soak to remove all water.



  5. #25

    Default Re: Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CA

    Hi Peter, you're right about the scope of the machine. I've got a bit caught up with achieving something that is perfect that can produce something with very high tolerances. I've sat down and though a lot about what exactly I need from this machine. The machine will evtually have a dual spindle ATC setup with two 4 axis rotary units, if my future business goes as planned. For now this machine will just be designed as a single spindle machine with manual tool change spindle. I've loosened up the stiffness requirement a bit and worked out a refined scope for the project. I will build the final machine straight away, so no WillMill Junior anymore. I will however make a few simple material tests in order to ensure some kind of process reliability before casting the base and gantry.

    New Scope:

    Goals

    • Mill aluminium moulds
    • Good surface finish in aluminium
    • Have a very damp machine
    • Get experience with casting composites
    • Have fun!


    Requirements

    • Max deflection: 70N/?m
    • Positional accuracy over 100mm: 0.05 mm
    • Part flatness over 200mm: 0.03 mm
    • Vibration dampening properties
    • Must contain dust and chips
    • Benchtop machine


    Specifications

    • Gantry clearance: 120mm
    • Part size: 300x600mm
    • 1.5 kW HF spindle
    • 2x Nema 24 motor for X-axis
    • Nema 34 motor for Y- and Z-axis


    Features

    • Square linear rails and ball screws
    • Epoxy granite base
    • T-slot table


    I have not specified a part accuracy, but I'm fairly certain that I can get the positional accuracy to be better than 0.05 mm. The goal with the tolerances is to be able to machine somewhat of a press fit in aluminium, and I'm fairly confident I can achieve that by using precision grade C7 ballscrews and precision milled stock (0.01 mm flatness) to mount the linear rails onto. I think the flatness of the t-slot table and aluminium stock to mount the linear rails on will be a little better than specified by the manufacturer to give them some room for error. Therefore the machine will probably be a little more precise and increase my chance of milling "somewhat" of a press fit. The base of the machine will either be a thin t-slot table cast into epoxy granite, or just a solid piece of cast iron t-slot plate. The t-slot table will also have a flatness of 0.01 mm. I came up with a good idea today, the linear rails for the gantry could simply be mounted directly to the t-slot table - I will do this!

    Now there's still a lot for me to figure out, but for now I'll start designing the gantry for the machine. I'm still not sure weather or not I will use epoxy granite for the gantry or if it will be made of a composite consisting of fibers. - It depends on what I can get my hands on for cheap/free.

    ****End of scope****

    Peter I'll get in contact with some composite fabricators and ask for cutoffs... I think I'll be able to gather a lot of aluminium swarf for free. There is a machine shop about 8 km from where I live, so there's potentially a good source for aluminium swarf, otherwise I just visit the metal scarp yard... Wouldn't it be a lot better to use aluminium as filler compared to wood? I know my personal mix will depend on what I find haha, but I'm just curious since you suggested it.
    I've thought a lot about making the gantry bigger and use foam blocks to create void inside the gantry.

    You have a good point Peter. The wood will be a lot heavier. I just saw a video about it today and I wasn't sure just how much more it would weight afterwards, but I thought it would still be rather light. Luckily this will not be a problem for my product. It's a designer toy car that will be of very high quality... and the extra weight might just add an extra bit of luxuriousness when you pick it up ;-)

    I had no idea that I would need to dry the infused parts completely before infusing resin, thank you for mentioning this. - You keep bad things from happening.

    Regards William



  6. #26
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    Default Re: Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CA

    Hi William - Its the outside skins of things that do the work. So a stiff outer is needed say CF offcuts, But to have CF offcuts on the inside is a waste of material and extra cost so you either make hollow parts ( hollow parts may vibrate) or you fill the skin with something eg sawdust, sand etc. You will also need mass as its a mill, so perhaps the "core" is heavy such as steel swarf. Once you get the design rolling then you will need to do some inertia studies to figure out motor sizes. I don't think you should use N34 motors N24 or N23 will be heaps. But that will come out in the wash.

    Re infusion: water is the enemy and its not discussed or understood much in infusion processes. The people that know don't share much as they have industrial processes tied up so things like vacuum soaking is not discussed much.... Infusion videos make it look very easy but like all skills and processes there are traps and tricks...If you read up on vacuum soaking air conditioning systems to flash off oil and impurities in the system this will give you some idea of what your up against. Peter

    By the way precision C7 does not exist. C7 is C7 and it has a spec. Precision in machines tools is a long way from C7...



  7. #27
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    Default Re: Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CA

    Hi William - If you intend making machines that work in your business I suggest that you don't. Far easier and more profitable to get a loan, make parts earn money and pay off the machine plus it will have a resale value at end of life. If your going into business a biz plan is good to have. "Business" is totally different to what we are discussing. But that's for you to figure out.

    So can the machine shop make parts for you as well? maybe good to get them to quote on some parts to establish a commercial value vs a backyard value... Peter



  8. #28

    Default Re: Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CA

    Hi Peter - Great feedback as always. Good point about the fact that hollow parts vibrate, I would never have though of that although it makes sense now that I think about it. Ahh yes the motors... Yes alright, I might intuitively have overestimated the motor requirements after watching some of Datrons high speed machining videos haha. The thought behind the madness was good acceleration, but as you said we will figure those things out when it becomes relevant

    Infusion: You're putting some golden advice out there peter, I'd like to thank on behalf of the forum. I'll definitely look more into vacuum soaking.

    Regarding the ball screws: I wrote precision regarding the grade, like 'the grade of precision'. On another note I'll probably end up buying some better ball screws then.

    Yes I'm 100% aware that it doesn't make sense to build your own mill for business purposes. Time = money, and time could be spent better elsewhere for business purposes. Regarding my business I had been selected at a talent program for young entrepreneurs where I won the award for best business plan, but since then things have changed a bit.
    - Funny story: The awards was about to be given, but nothing had happened for the last 30 minutes and I REALLY had to pee. I quickly ran out to the toilets to pee as fast as possible and get back in a hurry. I rushed though the door to the rooms where they would announce the awards for all the business ideas, and when I came inside I was presented with 100's of quiet faces turning towards me. I had won the main prize (best business plan), but it was announced 20 sec before I entered the room. Was a bit awkward to be honest.
    It's been a little dream of mine to build a CNC machine since I was 14 years old, so this project is worth my time even though it doesn't make sense from a business point of view.

    Good idea, it would be fun to calculate a commercial value for the build at the end of the project.

    I've created the build thread! --> https://www.cnczone.com/forums/open-...ml#post2371822
    - I'll write a little post tomorrow linking to some great articles that I found on your Maximus design thread for people to read if they find that sort of stuff interesting. I'll also give you some credit in that post. I would initially just write it now, but bedtime was 4 hours ago, so I'll let it wait a day.

    Regards William



  9. #29
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    Default Re: Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CA

    Hi William - Making the machine could for fine for the business, just need to be clear on why and clear on economics. Don't reinvent the wheel too often... Cheers Peter



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Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CAD

Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CAD

Router Design Research - Help me find more GANTRY DESIGNS to SIMULATE (FEA) in CAD