Markforged Metal 3D Printer Reviews: Additive Manufacturing vs. CNC Milling vs. Laser Cutting for Rubber

Markforged Metal 3D Printer Reviews Usually Miss the Same Thing

Last month, I got an email that shows up more often than it should: Can a Markforged metal 3D printer replace our machine shop for emergency parts? The short answer is no. The longer answer is more useful. In my role running production support at a 40-person contract manufacturer, I have triaged more than 100 rush orders in six years, including same-week turnarounds for defense and aerospace customers. The first question that matters is almost never which printer to buy. It is which process gets the part delivered with the least risk.

Most Markforged metal 3D printer reviews I read start with print speed, build volume, and tensile numbers. They usually leave out the part that determines whether an urgent job succeeds: routing. A Markforged additive manufacturing system is excellent for some geometries, quantities, and materials. It is not excellent for everything.

A useful review also asks what happens after the build finishes. Test coupons from a well-run demo look great. The harder question is whether your part, with your layer orientation and your post-processing, still matches the published data. Markforged publishes material datasheets. Use those as a starting point for approval, not as a guarantee.

So instead of a generic seven-step comparison, here is the scenario map I use with my team when the clock is already running.

Scenario A: Markforged Additive Manufacturing for Low-Volume Fixtures and Complex Composite Parts

Scenario A is the reason we added a Markforged to our floor. The part is a composite fixture, jig, drill guide, mounting plate, or low-volume production aid. It has features that a single tool cannot reach, or it changes shape often enough that CNC programming and setup do not pay off. The quantity is usually between 1 and 30 pieces—maybe 50, depending on geometry and delivery date.

On a Markforged, Onyx forms the matrix and continuous carbon fiber goes into the layers that carry load. That is different from carbon-fiber-filled plastic filament. It lets you make rigid, low-weight parts that still survive shop-floor use. The design is prepared in Eiger, fiber paths are confirmed, and the build starts without waiting for a fixture or a machinist.

In March 2024, a defense supplier needed 14 fixture arms before a scheduled line change. Our normal machine shop quoted nine days. We printed all 14 on the X7 in four days, including the first-article check. Those arms were not cheaper by weight—or rather, they were cheaper in the only metric that mattered: elapsed time.

Granted, if that machine shop had open capacity, it might have delivered in two days. The point is not that 3D printing is always faster. The point is that additive manufacturing removes setup, fixturing, and material ordering from the critical path. For urgent composite fixtures, that is often enough to win the week.

Scenario B: CNC Milling When the Part Is Metal, Prismatic, and Repeated

Now flip the scenario. If the part is a metal bracket with datum bores, counterbored holes, flat sealing faces, and a quantity above 50, a milling machine is normally the right answer. The same is true when the tolerance or surface finish is too tight for printed metal without secondary work. In this scenario, urgency does not make 3D printing better. It just makes the planning window smaller.

Ask the shop for its CNC milling machine parts PDF—many good shops publish one. The PDF will show standard corner radii, minimum wall thicknesses, thread depth, and feature size limits. Use it to design parts that can be cut with standard tooling. That is what turns a slow machine shop quote into a fast one.

How Does a Horizontal Machining Center Work?

If the part requires machining on multiple faces and the design is stable, someone will eventually mention a horizontal machining center. To answer a common question directly: a horizontal machining center works with the spindle axis parallel to the floor. The workpiece is mounted on a tombstone or pallet that indexes to different faces while the spindle removes material from the side. Chips fall downward, which helps with coolant and chip evacuation. It is an efficient way to make prismatic metal parts in volume.

But it is rarely the best answer for one-off rush parts, because tombstone setup, fixture design, and offline programming consume the time you do not have. That is why I route most one-off emergency parts to either a vertical CNC or additive manufacturing, depending on material. The horizontal machining center becomes the right answer when the part has stabilized and the quantity justifies the setup investment.

Scenario C: Use a Laser Cutter for Rubber Instead of a 3D Printer

The easiest scenario to miss is soft materials. If the request says rubber gasket, isolation pad, seal, mask, or soft-touch pad, stop thinking about layer-by-layer printing. A laser cutter for rubber will cut flat elastomer sheets into finished parts with no mold and no tooling. For quantities from 1 to 1,000, it is usually faster than any additive or machining option.

A laser cutter for rubber has real constraints: the material needs to be laser-compatible (neoprene and EPDM are common choices), the area needs proper ventilation, and the part has to be a 2D sheet design. It is not the answer for a solid rubber block or an overmolded part. But for sheet gaskets, it belongs in the decision map.

One of my favorite repair jobs used both tools in the same afternoon: an Onyx mounting plate on the Markforged and a rubber isolator cut on a laser system. The quoted alternative was a machined aluminum part plus a molded rubber component with a five-day lead time. We finished in hours.

How to Tell Which Scenario You Are In

Use four filters, in this order:

• Material. Elastomer or soft sheet material? Scenario C. Thermoplastic or fiber-reinforced composite? Scenario A. Wrought or cast metal with tight tolerances? Scenario B.
• Geometry. Deep undercut, curved internal channel, lattice, or organic shape? Scenario A. Flat faces, drilled holes, bosses, and straight tool paths? Scenario B. Flat sheet profile? Scenario C.
• Quantity. One to thirty parts with active design changes? Scenario A or C. Fifty or more parts with stable design? Scenario B or C. Large volume usually points to molding, stamping, or casting rather than 3D printing.
• Post-processing capacity. A Markforged metal part is not done when the print finishes. You need support removal, debinding, sintering, and sometimes finish machining. If those steps are not available, do not bet a Friday deadline on metal printing.

When the answer lands in two scenarios, prioritize the process with the fewest unknown variables.

Final Thought: Match the Process to the Risk

From the outside, it looks like adding Markforged additive manufacturing means replacing subtractive thinking with additive thinking. The reality is the opposite. Efficient shops use both. They print fixtures and complex composite parts, machine the parts that belong on machines, and cut sheet rubber on the right laser system. The efficiency is not in the technology. It is in not making the deadline wait while you force a part into the wrong process.

Last year, I assumed a metal 3D-printed bracket would skip CNC entirely. It did not; the datum bore still needed a light machining pass. That is not an argument against metal printing. It is an argument for counting finishing time in the schedule.

If you are comparing Markforged metal 3D printer reviews, look for reviews that mention post-processing and workflow risk, not only impressive test coupons. Then route the actual part before you route the budget. That is the decision that saves the order.