Kossel Mini Variant – opening thoughts

Kossel Mini Variant – opening thoughts

I have decided that my next printer will be a delta printer, and although I have come up with numerous designs, the most recent one seems to be verging towards that of a Kossel Mini, so why not simply build a variant of one of these and have done with it.

Now I could buy a kit of printed parts for $39.99 (£25.76) + $11.81 (£7.61) P&P plus some additional import taxes, but decided instead that since I already have a 3D printer, lets stop being lazy and use that to print the parts and save a few more pennies.

The aim is to complete the build for under £200.00, ideally under £150.00, which I believe is very achievable compared to a purchase price of about $1125.00 (£721.15) for an off-the-shelf version.

Cost of PLA printed parts

Filament Cost Total
Part (mm) (cm3) (£) Qty (£)
Effector 5.139.8 12.4 0.176 1 0.176
Frame Top (20×20) 13704.1 33.0 0.469 3 1.408
Frame Motor (20×20) 34007.6 81.8 1.165 3 3.495
Carriage 5717.9 13.8 0.196 3 0.588
Bowden Extruder 13719.7 33 0.470 1 0.470
Total 6.137


Cost of Vitamins and Electronics
Cost Total
Part Supplier ($) (£) Qty (£)
20×20 profile 600mm Motedis 2.46 1.58 3 4.73
20×20 profile 240mm Motedis 0.89 0.57 9 5.16
Slider for 20×20 profile Motedis 2.71 1.74 3 5.22
Carbon fibre Tube 5mm OD, 3mm ID, 180mm (6) Robotdigg 5.00 3.20 1 3.20
Tie Rods & Ball Joints (12) Robotdigg 7.00 4.49 1 4.49
GT2 Belt Loop 1350mm (675 tooth) Robotdigg 2.40 1.54 3 4.62
Geared Nema17 Stepper Motor Robotdigg 28.00 17.95 1 17.95
Filament Gear Drive Robotdigg 4.00 2.56 1 2.56
Nema17 Stepper Motors Ebay 12.55 8.04 3 24.13
J Head Hot End Ebay 24.94 15.99 1 15.99
Sanguinololu IteadSutdio 4.68 3.00 1 3.00
ATmega1284P RS 7.80 5.00 1 5.00
Step Stick Stepper Drivers Ebay 2.30 1.48 4 5.92
F623ZZ Bearings Ebay 0.78 0.50 6 3.00
Total 104.97

I ordered some Sanguinololu boards from IteadSutdio a while back at $22.00 (£14.10) for 10 boards, the components, are made up from various bulk orders I have made in the past (thousands of resistors for $0.99, thousands of ceramic capacitors for $4.99, hundreds of radial electrolytic capacitors for $8.99, 10 packs of 40 pin headers for $2.99, etc), I boosted the total cost of board plus components to £3.00 to include some decent connectors, rather than just pin headers.

I don’t bother with FDTI chips on the Sanguinololu boards, or the associated components, I either program them via the ICSP header if I need to burn a bootloader, or an external FTDI serial programmer if just updating firmware, I also use bluetooth modules for wireless communications.

M4 or M5 T nuts I buy from Robotdigg at $7.50 (£4.80) for 100, other nuts, bolts and washers I buy from Orbital Fastners in quantities of 100 or more. Something like M4x25mm Allen Socket Button Screws are £3.72 ($5.80) for 100, I just order multiples of 100 as I use them up pretty fast anyway.
As such I will allow a fairly generous figure of £10.00 for nuts, bolts and washers, bringing our total thus far to around £120.00.
I do not want to use a heated bed, so this will save huge amounts of power and I will be able to use one of my many surplus laptop power supplies as a power source.
The print bed will be an 8mm disc of acrylic that has been sanded on one side to give a frosted appearance, this should allow PLA prints to stick yet still be removable once the print completes – a 175mm disc of 8mm acrylic can be had on Ebay for £10.70 ($16.70).

I am intending to try the Acetal Slider from Motedis instead of linear rails, I am not aware of anyone trying this idea before, and I have no idea how well it will work – it may have way too much slop to be of any real use, but at only £1.74 ($2.71) per axis, they have to be worth a try.

If this does not work, then I can use their Acetal rollers instead, these are designed to run in the 6mm slot on the side of the 20x20mm profile, these are £2.67 ($4.17) each, and I would need 9 or more, so I think it is worth the shot on the sliders first, many people have made alternate carriages to run on similar wheels/rollers, so I should be able to adapt one of these fairly simply.

Then there is always the fallback option of Chinese Linear rails at $58.00 (£37.18) from Robotdigg for a set of 3 x 400mm rails and carriages.
Even if end up I trying all 3 options, the total cost should still be well below the target of £200.00.

Leave a Reply