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  1. #131
    Hi guys, had some time recently to get some more done on the router. I had to get it out of the office and onto the shop floor so made a makeshift bench for it, it weighs about 80kg and is pretty sturdy, i bolted the router to the bench using M8 T Bolts.

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    With that done i set to work on the aluminium plates, i ended up purchasing the stock from the Aluminium Warehouse, i started with the most basic 5mm thick plates. It went pretty well, i tried to look at a feed / speed calculator to get a rough starting point but all of them were in inches or didn't actually give me the data i needed, i think i need to hit the books a bit more on that. I didn't purchase any additional tooling as i had a few 5mm Twin Flute Carbide tools sitting around, these seem to perform ok but are terrible at plunging and are very difficult to keep cool with air, i ended up running at 16,000RPM & 1m/min with cut depths of 1mm - as the machine is the opposite of rigid this seemed to "work" but is clearly not correct as a lot of heat was generated and i had to stop mid way through one plate as the spindle sounded as if it was going to stall!

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    https://www.youtube.com/watch?v=iU3ciLg19es

    I'm looking for some advice on what tooling i should be using, how to calculate the correct speeds & feeds etc.

    Should i be reducing the entire stock to achieve the part, as opposed to simply cutting out the part from the stock?

    I watched one video where the guy drilled holes prior to pocketing, is this a good way approach plunging? Or is the a better / correct way to do this.

    Any help is greatly appreciated.

    Thanks

  2. #132
    Double stick tape to hold down and cut the aluminium is a risky way to do the job. Better make the holes first and then use screws to hold down on your table the aluminium plates ,this way you minimize the risk of slippage. ;-)

  3. #133
    Quote Originally Posted by Nickhofen View Post
    Double stick tape to hold down and cut the aluminium is a risky way to do the job. Better make the holes first and then use screws to hold down on your table the aluminium plates ,this way you minimize the risk of slippage. ;-)
    Yes i know its not ideal, i came across this method online a few times so thought i would try it, it's masking tape on the spoilboard & plate with Super Glue in between, it was actually very difficult to get off :P

    Thanks
    Last edited by AlexDoran; 13-03-2018 at 10:33 AM.

  4. #134
    Quote Originally Posted by AlexDoran View Post
    I watched one video where the guy drilled holes prior to pocketing, is this a good way approach plunging? Or is the a better / correct way to do this.
    First, a word of warning about double sided tape... don't use it to attach aluminium to MDF. I don't think it is a good idea because it doesn't stick well enough and is flexing in every direction. In my opinion double sided tape is only usable for PCB or acrylic, possibly thin aluminium (maximum 2mm) for panels. It is also OK for engraving, but not when you are pocketing or milling thick aluminium or other thick material. Use a vice or drill a few holes and screw the plates firmly to the MDF.

    Regarding pocketing, yes, in my opinion it is a good idea to pre-drill large holes. It saves time and material, as well as tools. It is much faster and easier to drill or saw even a very large hole compared to milling all the material, but it requires fairly accurate positioning on both the drill stand and then the CNC bed. I drill or saw a bit smaller then needed and mill it to the final dimension with the CNC. I have a set of drills and circle saws so I can drill from 0.5mm up to 70mm and if I'd need to make even larger holes I'd buy larger (note that the quality is high On aluminium I am using 4 flute 4 or 6 mm diameter cutters, 18k RPM. I am dry milling, not using any lubricant or any spray. Probably it would be better to use something, but I chose not to because of the CNC location (inside my house in an ordinary office like hobby room). Anyway, regarding the cutter, I have no issues with chips welding to the cutter, but I try to keep a fairly high feed rate and it seems to work fine.

  5. #135
    Hi guys! It's been a long time since my last post, i had been using the machine steadily for some light work but eventually got round to finishing the Aluminium parts and EVENTUALLY got round to rebuilding the Router. During the rebuild i realized i had made on one of the Gantry Connection Blocks, that interface the Gantry Side Plates and Gantry Base Plates, i managed to "make do" with it to get the Router back up and running, i am going to re-run this part in the very near future.



    It took me a very long time to try and make the Gantry Linear Rails as true to the X Axis Rails as i could, unfortunately my only Straight Edge to hand was a length of spare Aluminium - I know this was not ideal, but the run out i was seeing using the Dial Indicator was repeatable using different Ends and Sides of the Extrusion which gave me a slight amount of confidence that the faces were pretty straight.



    The Gantry Extrusions were fixed - i would say as straight & true as possible using the tools i had on hand to gauge it by, however i was still seeing almost 0.8mm runout from one end of the gantry to the other, The Gantry Base Plates were exactly the same distance from the Linear Rails on either side, besides this i was really struggling to get the Gantry Rails parallel to the X Axis Rails, after some research i discovered that i might need to shim the rails from the extrusion in order to reduce the runout, this helped in some areas but made it worse in others.

    If i performed the same tests but clamped the Extrusion to the Flat Face of the Entry Side Plates then the runout measured was less than 0.2mm from End to End, having spent the best part of 6 Hours on it i decided to leave it there. I am almost certain that something is amiss somewhere, and if anyone had any ideas on how best to measure and correct the runout that would be greatly appreciated, i am hoping to build a mill soon, and i am sure as hell not going anywhere near Extrusions for that!



    Once i started to Assemble the Z Axis i realized that Connection Blocks that Space Between the Linear Bearing Blocks and the Spindle Mounting Plate were about 0.4mm too thin, this meant that the Ballscrew and Nut were becoming Extremely Tight at the far ends of the Axis, so i had to shim between the Blocks and the Spindle Plate, now it seems to be moving very smoothly.

    I had to drill and tap some holes on the fly to the rear of the Z Axis Base Plate (Forgot about those... doh!) to bolt the Cable Drag Bracket to the Base Plate.

    Next i put the Spindle back on and reconnected everything, setup the Limit / Home Switches for the new parts and ran some tests. At a first glance the Spindle seemed to be trammed ok, however i need to get some other bars for my Dial Indicator so i can connect it to the spindle properly and get it dialed in as much as i can. I also 3D Printed a Makeshift Dust Shoe until i can draw up something to be machined from Aluminium.





    I still need to do the following:

    - Machine the Aluminium Cross-member / Backing Plate for the rear of the Gantry.
    - Add more Horizontal Extrusions to the base of the machine, so that i have more places to fix the Spoilboard down, in some areas i think it is now dipping in when surfacing. Fortunately i have about 3 meters spare so i can do this pretty soon.
    - I need to decide whether it is a good idea to try and surface the Horizontal Extrusions that the Spoilboard sits on, or if this is a pointless task and to just try and surface the board as best possible.
    - Get a more powerful Extraction Hoover.
    - Get a Mist / Air Blower, was looking at this one, it seems to have a few good reviews: Amazon
    - Machine some Endstops for the Linear Rails.
    - Machine some Nema Mount Spacers from Aluminium (Currently Still 3D Printed but seem ok).
    - Run some Nylon Tubing to the Ballnuts where i fitted Pneumatic fittings to pump Grease through.
    - Find a damn "Needle Grease Gun" for these miniature Linear Rail Blocks.
    - Wire in an E Stop to the bench or Controller Housing somewhere.
    - Machine the Controller Housing from Aluminium.
    - Fit some Brackets to Bench so that the Controller has somewhere to rest.

    Usually i have been using Aspire to do all of the Sheet work & Drag Knife stuff, however i dont like it for machining Aluminium parts. Previously i created a Post for the DDCSV1.1 to be used in Solidworks and SolidworksCAM. I lost this config when my Hard Drive failed last year so i sat down to re-do it. However i finally decided that i didn't really like SolidworksCAM, it's features to find and generate operations for machinable sections of the model never seem to pickup or identify things as you would want it to, you ALWAYS have to go in and modify the definitions it creates, which i think actually takes longer than creating them manually, the only exception to this is Drilling. So i decided to try HSMXpress, which is basically a Fusion360 Toolpath plugin for Solidworks, which works VERY well, i ran my first aluminium part using the Adaptive Toolpathing / Clearing and am very impressed, i think i was running slightly too fast for the machine - but Speeds / Feeds / Chip Loads is an area im very uneducated in so im desperately following some tutorials to try and get this nailed. Here is the extraction hose guide i machined as a test:



    After Roughing:



    Finished - Minus the Clamping Holes i drilled and tapped manually:





    Here is a video of the adaptive clearing, i think i was running too fast, you can hear some resonance - 18000RPM | 2.5mm/min | 19mm DOC | 0.5mm Stepover.

    https://www.youtube.com/watch?time_c...&v=OwfTLmSoAUY

    Since i share the Solidworks license with someone at work i exported all of my Libraries and Configs to Fusion360 which is where i will do all my CAM work now.

    I've also been using the Donek D2 Dragknife for cutting 2.5mm Fire Retardent Interdens for some Door Ironmongery too, its a great bit of kit and paid itself off in labour time alone on its first sheet cut, usually the bench joiners would cut these by hand.

    https://www.youtube.com/watch?v=DJLdbcvptbU

    I also need to do alot of reading on the best way to clamp more complex aluminium parts, i was looking for a cost effective but accurate vice that i could fix to the spoilboard or maybe even the Extrusions under it, then start using softjaws if needed.

    Thanks

    Alex
    Last edited by AlexDoran; 26-07-2018 at 11:22 AM.

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  7. #136
    Quote Originally Posted by AlexDoran View Post
    - I need to decide whether it is a good idea to try and surface the Horizontal Extrusions that the Spoilboard sits on, or if this is a pointless task and to just try and surface the board as best possible.
    What if you mill / surface the X-axis extrusions so that the linear guides sit flatter? Isn't that the source of deviation you talk about?

  8. #137
    Quote Originally Posted by jparamo4546 View Post
    What if you mill / surface the X-axis extrusions so that the linear guides sit flatter? Isn't that the source of deviation you talk about?
    I am not sure where the deviation is coming from, the deviation is present all the whole X Axis so I'm not sure if Maybe the machine is not bolted down flat.

    Unfortunately I have no reliable way to mill those extrusion accurately either.

    Thanks

    Alex

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