Genmitsu 3018-MX3 Complete Setup Guide: Assembly, Stock Controller, and Your First Cut

The SainSmart Genmitsu 3018-MX3 sits above the base 3018 and 3018-Pro in SainSmart's entry-level lineup, adding a new controller board, limit switches, a Z-axis zero-out tool, better clamps, and a pre-installed ER11 collet chuck for around $350 — roughly $100–150 more than the plainer 3018 variants. It's a genuinely small machine with a genuinely small budget, and getting the most out of it means understanding exactly what that price difference buys you and where the stock setup falls short.

What's Actually in the Box, and What It Buys You

• Work area: a measured build volume around 262 × 155 × 37 mm once limit switches and travel are accounted for — this is a machine for small parts, PCB work, and detail carving, not sheet goods.
• Spindle: a single-speed spindle powered from the included 24V, 5A supply. Several long-time owners report a worthwhile power and finish improvement from swapping to a 36V supply with a compatible board, since the stock 24V setup leaves real performance on the table.
• Controller: this is the biggest departure from most budget CNC routers covered elsewhere on this site. The MX3's stock board is built around Mach3/Mach4 control rather than the GRBL firmware most hobby CNC software (Candle, UGS, gSender, bCNC) expects. Mach3 licenses run roughly $175, and Mach4 has its own cost tier as well — budget for that if you want to run it as designed out of the box.
• ER11 collet chuck: pre-installed on the spindle motor from the factory, saving you the fiddly first-setup step of mounting it yourself.
• Limit switches and Z-zero tool: both absent on the cheaper 3018/3018-Pro variants, and both genuinely useful for repeatable homing and tool-length setting.

Assembly

The printed manual that ships in the box is thin; lean on SainSmart's detailed assembly PDF instead, which covers the build in far more depth. Realistic assembly time is a couple of hours for someone comfortable with a hex key and basic mechanical assembly. Acrylic panel pieces are included for parts of the frame — handle them carefully during assembly, since cracked acrylic is a common first-build mistake on machines in this class.

The GRBL Question

If you want to run this machine with the same GRBL-based software ecosystem covered elsewhere on this site — Candle, UGS, bCNC, or a webcam/Raspberry Pi-based GRBL workflow — you have two realistic paths:

1. Run it stock with Mach3/Mach4. This works, costs extra for the software license, and locks you into a Windows-centric workflow that's noticeably different from the free, cross-platform GRBL senders most budget CNC guides assume.
2. Swap the controller board. A common upgrade path among 3018-MX3 owners is replacing the stock board with a GRBL-compatible controller (a Woodpecker-style board is a common choice in the community), which opens the machine up to the same free software stack — Candle, UGS, CNCjs — used across the rest of the budget CNC ecosystem. This is a genuine hardware modification, not a firmware flash, so it voids any remaining warranty consideration and requires comfort with rewiring stepper and spindle connections.

If you're specifically buying this machine expecting a GRBL-out-of-the-box experience like a Shapeoko or a WolfPawn, the stock MX3 controller will catch you off guard — confirm which controller generation you're receiving before you commit to a software workflow.

Your First Cut

1. Home all three axes using the limit switches, then zero your Z height using the included zero-out tool rather than eyeballing it against the stock material — at this machine's small Z travel (37 mm), a few millimeters of error in either direction is a meaningful fraction of your usable depth.
2. Start with a soft material — basswood, MDF, or a soft wax/modeling board — for your first toolpath, using light depth-per-pass settings. The single-speed spindle and light frame don't tolerate aggressive stepdowns the way a heavier, VFD-spindle machine does.
3. Run a simple 2D profile or pocket cut first rather than a 3D relief carve, so you can confirm homing, Z-zero, and basic feed rates are behaving before attempting anything more complex.

The 3018-MX3 is a reasonable choice if you specifically want the mechanical upgrades (limit switches, Z-zero tool, ER11 chuck) over the cheaper 3018/3018-Pro and are prepared to either pay for Mach3/Mach4 or do a controller swap to get GRBL support. If you just want the cheapest path into GRBL-based small-scale CNC, a plainer 3018-Pro plus a GRBL controller and your own end stops may end up being the better value for the same total spend.