Prusa MK4S vs Core One: Open-Frame or Enclosed CoreXY?

If you're buying a Prusa today, the real decision usually comes down to two machines: the open-frame MK4S and the enclosed Core One Plus +. They share much of the same DNA — the same Nextruder, the same firmware ecosystem, the same Prusa reliability — but they're built around two different motion systems and two different ideas about what a printer should be. Here's how to choose.

The Core Difference: Motion and Enclosure

The MK4S is a bed-slinger: the bed moves on the Y axis while the toolhead handles X and Z. It's open-frame, proven over many generations, and exceptionally easy to maintain and upgrade. The Core One is a fully enclosed CoreXY: the bed only moves down in Z while a lightweight gantry moves the toolhead in X and Y, with an actively heated chamber. CoreXY plus an enclosure is what unlocks reliable ABS, ASA, PC, and nylon — and it holds quality better on tall prints.

Head to Head

The MK4S: Proven Open-Frame Workhorse

The MK4S is the printer that built Prusa's reputation, refined across many generations. Its open design makes maintenance and upgrades genuinely easy — every part is accessible, documented, and replaceable. The custom high-flow nozzle pushes volumetric flow to around 24 mm³/s and the 360° cooling enables clean overhangs, so it's far faster than its bed-slinger layout suggests. For PLA, PETG, and TPU — the materials most people print most of the time — it's superb, and it's the more affordable entry. Add the optional enclosure later for occasional ABS/ASA, or the MMU3 for multi-material.

The Core One: Enclosed, Faster, More Capable

The Core One is Prusa's modern enclosed CoreXY platform. The active chamber (up to 55 °C) and sealed enclosure mean ABS, ASA, PC, and nylon print reliably without warping or layer cracking — materials that need an add-on enclosure and patience on the MK4S. It's roughly 15–20% faster than the MK4S, has 50 mm more Z-height (250×220×270 mm), and takes up less bench space than an MK4S fitted with an enclosure. It can even print PLA and PETG with the door closed, something most enclosed machines struggle with due to heat buildup.

Which Should You Buy?

Choose the MK4S if: you mostly print PLA, PETG, and TPU; you value the open, easy-to-maintain design and the lower price; and you don't routinely need engineering materials. It remains one of the best open-frame printers made.

Choose the Core One if: you need ABS, ASA, PC, or nylon reliably; you want the faster CoreXY motion and more Z-height; or you simply want the most capable single machine and a tidy enclosed footprint. It's the better long-term platform if your material needs are growing.

Still deciding between open and enclosed across the whole range? See our complete Prusa buyer's guide, or — if you're cross-shopping Bambu — our Core One vs Bambu P1S/P2S comparison.

Available from Eolas Prints — Authorised Prusa Reseller

Both the MK4S and Core One Plus + are genuine Original Prusa machines, supplied with full manufacturer warranty and EU support and shipped from Spain. As an authorised Prusa reseller, we can advise on the right choice for your materials and workflow — just get in touch.