[NidalRobb]

This is a summery of my entire build 50"x50" KRMx02. My main build log is hosted on kronosrobotics forums. This is only showing my main text entries and ideas/thoughts i went through during the build. I will also show pictures/videos. I omitted the metric sizes i used myself but if anyone interested they can get it from the main build log or just request it here and i will add it.

To make things faster, some of the text here will be exact copy/paste from text i wrote on the main build log

I am building this CNC in Dubai.

First bump on the road is that 80/20 material with that huge weight is going to cost 140% more than the cost of the material itself to ship here. or around 80% of the cost of the material if shipped by sea as its not full container load but part of a container and for that distance that is at least $900 for sea freight and on top of that, it needs a whole month to get here! 80/20 sells Pre-Cut to length & Tapped AL extrusion kit on eBay. This cost $1,242 + Shipping

CRP (CNC Router Parts) kit is not heavy so that is ordered and is on the way. So the decision was either i get the profiles from the US with its 'Inch" spacing T-Slots and stick to the design with huge added cost. Or get an "mm" spacing T-Slots and slightly adjust the design and so some saving!

With the high cost of shipping that far out, i managed to get the profiles from a major industrial factory in China for 60% of the price in the US and much cheaper shipping.

The material is of equal mass/strength as 80/20 so i am not worried about the quality but of course this needs to be verified once i get the material here next week.

The Metric AL extrusion from China is around $750 with longer lengths as well (2 meters each)

I did put a lot of hours studying the design and i already figured out most of the small changes in the design lengths to accommodate for slightly different Profile data. The difference is that 80/20 extrusion has 1.5" spacing (center to centre) between the Slots. Metric Profiles uses 40 mm difference. Plus height/width are different as well. I am using 80x160 (mm) in place of 3060 and 80x80 (mm) in place of 3030. I probably will keep the 1530 section (Z axis) as all CRP kit requires the 1 1/2" T-Slot spacing.

[NidalRobb]

The second bump is that Cold Roll steel is not really available out here... in fact, steel could be anything without really knowing what it is. Unless you order in HUGE quantities for a skyscraper project otherwise you dont get what you want and can't guarantee what you get. So with some calculations, it turns out that i can get an 8x4' stainless-steel sheet, have it CNC laser-cut and all holes are already cut out i provide the CAD/CAM code with just a little $$ more than the steel price itself! and i get to save a lot of time tapping & drilling!

Considering the KRMx02 have A LOT OF HOLES that needs to be drilled, over 300 into steel. I hate drilling 1/4" Steel, and these needs to be accurate/aligned holes really!

So i saved a lot of time by using Stainless-Steel sheet. Its the same weight as Cold Roll Steel, i dont need to paint it as it wont rust!, i can have it mirror finish or mill finish. Most probably will be SS 304, but SS 201 is 20% stronger than SS 304 but less resistance to rust but its not an issue indoor.

I supplied a Vectric Aspire file to the CNC workshop and they quoted US $550 to supply the sheet + laser-cut + BENDING the right Angle after cutting as the file includes the RA profiles flat so the holes can be cut out. I think that was really a very good price. I used SS 201.



I even had empty spaces on the sheet to make extra jigs, stoppers, braces and so on. The cost of the CNC workshop is per time so was just an extra $20 to cut extra pieces. So Total cost of the SS 201 sheet + Laser cutting + Bending 4 pieces to Right Angle is $570. Note that i have to supply the CAD file myself so any error in file is on me!!

Result came out good and perfectly aligned. now just going to decide on polishing/cleaning and keeping this 'industrial' look or do a mirror finish for a different look. Kinda glad i saved myself drilling (and measuring/aligning) over 300 holes!

Bending RA is 90° perfect but they were suppose to use a press that does BD (bend deduction) so when i supply a CAD design with 162mm flat length piece (for example) then bending it would give 80mm each side. But they ended up using a machine that does BA (bend allowance) so I ended up with 87mm on the vertical side and 80mm on the horizontal side. That is fine, it just mean i can shear 7mm from that side or just have the Z rises 1/4" extra.

[NidalRobb]

Been getting the table stand ready while still waiting on stuff to arrive. Profiles are on the way. McMaster-Carr do not ship overseas, i need to get 3 pcs of 72" Racks. Ahren from CRP was very helpful in regards to the Racks. He agreed to get them for me @ 72" length and ship them along with my kit. Thanx Ahren.

While waiting for orders to come, i started working on the stand/table design.





I went ahead with mirror finishing all Stainless-Steel pieces. They really came out great. I used 1500 grit on last pass!







Also, the table is getting close to be finished here. Note that i ended up chopping the wheels/casters off as i initially welded these in place.





China order arrived. These Metric AL extrusion profile are really great. Strong, and very good quality. Here are some pictures and link to the supplier in China, if anyone interested, i can send them the email address of their english speaking salesman (Thomas) but gotta check with him first to ok his direct email being posted on the forum on he may provide me the general email address.





The extrusion profiles are great. I was worried China profiles are weak, but it turns out that 8080 is stronger than 3030 (Mass, weight/length), also 4080 (which replaces 1530). But 80160 is slightly less. it will do just fine.

For anyone who likes light reading in bed.. here is the link:

http://www.sh-mjly.com/eng/products....cs&ClassID=102

Started to cut the AL to size as its all came in 2000mm length. And of course drilling 80160 for the Right Angle build/Y-Beams.

Now here are some pictures during the build:

[NidalRobb]

Here is a video of its first run test. Initialy (in the first part of the video) the speed was set to 1000 ipm. Then i stopped it i run the 1500 ipm. No sweat. I think this machine can do 2000 imp easily!

First Test!

Now doing the control box, E-Stop switches & Z Height Probe!













Finishing the Table Top here:





The table top is actually three layers of 18mm MDF. The first layer is the one that is secured to the cross beams by 12 bolts countersink.

Then the second layer which is bolted to the first layer with another set of through bolts/nuts this time joining both sheets. This sheet is cut out around the Y-beams so it starts from the outer right angel to the outer other angle as you will see in the second picture. I think it gives a little extra space and it does cover the front of the y-beams to make it look better. Then the third layer are the T-Track sandwiched between MDF pieces. This is the layer that i will level.

The T-Track is 1/2" height. MDF is 18mm. So this gives around 6mm difference which is great. Going to take maybe 1/2 mm (0.02"). This gives me the chance to make this layer also the waster layer and i can keep levelling it until it reaches just 1mm above the T-Track then stop using it as a waster layer or just change it!

I used Clampusystems T-Track, nice quality and the price is right. These guys do have a nice selection of different vacuum tables and vacuum clamps as well, affordable also. May try a small vacuum table from them. Checkout their videos holding a 1000 lb load just on a vacuum! Anyone checked these guys out or tried their product?!

Now i attached the spindle/VFD. And using 2" Magnate Surface Planer bit to level the table top. I am changing the Step over setting to 20%. In this video, this run is done at 225 Hz (13,500 RPM), with Vectric Aspire setting at 225 IPM, 2" wide Bit, 0.2" depth, 40% Step over, estimated to finish in 24 min. I think 40% step over is little high as some lines are showing between the passes. So going to do it 20% step over with little higher speed/RPM to complete the full 50" x 50" area.





Leveling Video

[Trotline]

Impressive machine, and definitely the shiniest I've seen!

Luke

[pippin88]

Awesome build.

Are you able to share with us the prices for the aluminium extrusion? (if not publicly, by private message maybe?).
Is that the K series extrusion from Shanghai Minjian Alu?

Extrusions are stupidly expensive here in Australia (talking $100 a metre for 80x80mm (5kg a metre)).
Misumi (which a lot of the US guys use) won't deal with individuals here (via their Singapore branch)

Thanks,
Nick

[NidalRobb]

Awesome build.

Are you able to share with us the prices for the aluminium extrusion? (if not publicly, by private message maybe?).
Is that the K series extrusion from Shanghai Minjian Alu?

Extrusions are stupidly expensive here in Australia (talking $100 a metre for 80x80mm (5kg a metre)).
Misumi (which a lot of the US guys use) won't deal with individuals here (via their Singapore branch)

Thanks,
Nick

Well, shipping from China to AU may bring the price to that depending on how you will ship and custom procedure in AU.

The price i was given is retail and expensive also (compared to the factory volume pricing) I knew i can get better pricing if i order more quantity.

I got 80x160 (A style) @ $75 per meter
80x80 (A style) @ $48 per meter
and 40x80 (K style) @ $32 per meter

I think if you ask them to pre-cut to length then they will only charge you per length, for me i got 2 meter pieces and cut here as i needed extra for other projects.

I talked to Misumi Japan & China; they did not want to deal low volume.

Send email to Thomas in Minjian Alu, all english email goes to him.