4' x 4' x 8" Router Build

[JonnyFive]

It's been slow progress over the last few months. I've spent the last month or so trying to work out how much this thing is going to cost me, looks like it's going to be around £5.5k.

Here's what I got so far:

Steel box section for the frame:

I have scavenged some 80x80x3 box section from work; I have redesigned the top of the frame and the main leg uprights to use this, the rest will be 60x60x5 & 60x120x5 as previously planned. The price of steel is insane at the moment, it's going to cost £750 for the rest of the steel I need - my original cost was £500 when I priced up the entire frame a couple of years ago!! I've been trying to figure out if I've over engineered it, compared to most other designs I've looked at I seem to have an awful lot of steel in there.

Parts from BST:

Original HIWIN Brand Linear guide
2pcs HGR20-L1900mm Linear rail
2pcs HGR20-L1450mm Linear rail
2pcs HGR20-L400mm Linear rail
8pcs HGW20CC-ZA-C Carriage
4pcs HGH20CA-ZA-C Carriage
=USD629.00

Our own Ballscrew Assemble Set
2set RM2010-L1770mm ball screw with SFU2010 Ballnut
1set RM2010-L1480mm ball screw with SFU2010 Ballnut
1set RM1605-L322mm ball screw with SFU1605 Ballnut
All with end machining according your need,1770/1770/1480/322mm is the TOTAL length for each

3pcs 2010 Ballnut Housing
1pcs 2010 Ballnut Housing

1pcs OD25-8x10mm Jaw Coupling
1pcs MBA12 Motor Bracket
USD182.00

2set FK15/FF15 End support-Superior type,FK with P5 grade Angular contact bearing and FF with better deep groove ball bearing
1set BK15/BF15 End support-Superior type,BK with P5 grade Angular contact bearing and BF with better deep groove ball bearing
1set FK12/BF12 End support-Superior type,FK with P5 grade Angular contact bearing and BF with better deep groove ball bearing
6pcs M15x1 Locknut
2pcs M12X1 Locknut
USD145.00

1set 2.2kw spindle motor set=1pcs 2.2KW 220V 4 bearing motor+VFD+80mm Clamp+Water pump+Pipe
USD265.00

6pcs HTD-5M-20Teeth-15mm Wdith Pulley
4pcs HTD-5M-15mm Width-250mm Belt
USD22.00

1pcs 1000mm 25x38mm Cable chain with end connector
2pcs 1300mm 35x75mm Cable chain with end connector
USD26.00

Weight is about 57kg,discounted freight is USD650.00,so totally is USD1919.00.

= £1417

Aluminium extrusion for gantry:

2 off 160 x 80 x 1620mm (with drilling / tapping) = £1064

Aluminium tooling plate:

I've calculated approx £500. I was hoping to get these made for me but there is a maker space recently opened up near me that has a CNC mill so I am thinking it will save me some cash and be a good introduction to CNC to sign up and make them myself.

Closed loop steppers & drivers = £500

Electronics:

I've estimated £500 to cover the PSU, enclosure, cables etc - is this about right?

Miscellaneous:

Estimated around £500 (not including PC and software)


Is there anything obvious I have missed? Are my estimates about right?

I have reworked my frame to include the 80 x 80 x 3 that I have, I used it on the machine bed and the main uprights - I figured the bigger second moment of area compared to 60 x 60 x 5 would make these parts stronger. The frame now looks like this:






I am also pondering whether to have just a single aluminium extrusion for the gantry to save a bit of money. I can see that it adds a lot to the stiffness to the gantry but £500 each piece is a big investment. I have seen people get pretty good results on lesser machines with far smaller gantry sections. For example a single 160x80 section has a second moment of area 22x greater than a gantry made from C-beam. I'm not 100% convinced the extra cost will result in a significantly better machine - interested to hear what people think of this?

This is how the machine looks now: