A part comes off the press clean, the cavity filled, the cosmetic surface fine – except it’s still attached to a sprue and runner that have to come off before the part is done. That removal step is degating: cutting or breaking the gate, and usually the sprue and runner with it, away from the molded part. Get it wrong and you’re either looking at gate vestige out of spec or a bottleneck sitting right at the press.

What Degating Removes, Exactly

The sprue is the main channel that molten plastic enters through. The runner distributes it from the sprue to each cavity. The gate is the narrow opening where the runner meets the part itself, and it’s the gate that degating actually removes. What’s left behind afterward is called gate vestige, and its allowable size is its own spec – a cosmetic requirement on a visible surface, a functional one if it interferes with an assembly.

Your team already knows this vocabulary. The part that’s less obvious: how much of the degating step is still manual, and what that costs you.

Three Ways to Get the Gate Off

There are really only three places the trim can happen. An operator does it by hand, the robot does it on the arm, or a dedicated station does it after the pick. Each one buys you something and charges you for it somewhere else.

Option A: Manual Degating at the Press

Somebody standing at a press with a pair of side cutters or a hand tool, trimming gates part by part, introduces variance the rest of your process doesn’t have. One operator trims tight. The next leaves more vestige. Cycle time creeps because the trim step doesn’t move at the same pace the press does.

That inconsistency shows up downstream. A gate vestige spec that passes on the day shift and fails on the night shift isn’t a training problem – it’s a process problem.

Pros

• No engineering work and no upfront tooling cost

Cons

• Labor cost, and finding the labor at all
• Repetitive-motion injury risk, carpal tunnel included
• Inconsistent vestige and the quality escapes that come with it

Option B: Degating in the EOAT

The core idea is simple: pair a part gripper or sprue gripper with a pneumatic nipper on the same end-of-arm tool, so the robot grips the part, trims the gate, and clears the runner inside the same arm cycle it uses to pull the part from the mold. No second station, no separate trim step waiting in line.

Pros

• Lowest cost of the two automated options, since the EOAT frame is already there and doing work
• Nippers fire off the robot’s own controls, on the robot’s own timing
• No additional floor space
• No additional safety equipment

Cons

• Setup and adjustment after a mold change is slow and fiddly
• The more nippers on the plate, the harder consistent cuts get
• A robot tech or maintenance person is needed after every mold change
• Added hardware eats payload, and EOAT weight becomes the limit

Option C: A Dedicated Degating Station

ASS< builds fixed degating stations for shops that would rather take the trim step off the robot entirely. It’s the most application-specific, least generic thing we make, built around part-specific nesting and docking pins that locate the part the same way every cycle.

Pros

• Trim time comes off the robot’s cycle completely
• No payload penalty on the arm
• Part-specific nesting and docking pins locate the part identically every cycle, which is what holds vestige consistent
• Mold changes don’t mean re-teaching nippers on the plate

Cons

• Takes floor space
• Hardest to justify on high-mix, lower-volume work
• Most engineering up front, since the nest is built around one part

On the Arm or in a Separate Station?

This is a real decision, and it doesn’t split evenly. If you’re running high-mix, lower-volume work where a dedicated station can’t justify its floor space, put the nipper on the arm. If you’re running one part at high cadence on a single press, a separate station usually wins, because it takes the trim time off the robot’s cycle entirely and lets the arm move faster on the next pick.

There’s a payload argument that pushes toward the station side more often than people expect. Every gram of nipper hardware on the end of the arm comes straight out of usable payload; an ASN 50 ARK weighs just over 2 kilograms on its own, before mounting hardware, sensors, and the gripper it’s paired with. Heavier tooling isn’t automatically sturdier tooling – it’s slower tooling, and it hits harder in a crash. Run the payload math before you decide, not after the tooling’s already spec’d.

Degating Hardware: Bodies, Blades, and Timing

ASS< carries nipper bodies sized to the job. An ASN 10 AR closes at up to 588 N; step up through the AR line and an ASN 50 AR closes at up to 4,704 N – roughly eight times the force, for gates that need it. When a gate is tougher than a standard AR body can handle, the ASN-ARK adds a power booster: the same ASN 50 frame jumps to 7,742 N max closing force. That’s the kind of number a generic degating explainer never gives you, because a generic explainer doesn’t sell the nipper.

The blade doing the actual cutting is a separate wear part, and it’s sized to the body too – SEG straight blades come in body-matched variants like the SEG 30/50-0-41-S, with a listed weight of 356 grams and a steel alloy construction built to take repeated impact.

Timing matters as much as force. The GT-TC-02 air timer delays the port firing the nipper close by 0.5 to 1.5 seconds after the part-grip stroke fires, which lets a stroking nipper run off a single air line instead of needing two independently controlled circuits.

Matching the Blade to the Gate and Material

Nipper body size gets most of the attention, but blade geometry against material matters just as much. A glass-filled resin cuts differently than an unfilled one – it’s more abrasive and tends to be more brittle right at the gate, which changes what blade profile actually holds up. SEG blades are keyed to body and application rather than one-size-fits-all: the SEG 30/50-0-37-S and SEG 30/50-0-43-S are both built for the same ASN 30/50 frame but differ in weight and profile depending on the gate geometry they’re meant to trim.

If your current blade is wearing fast or leaving inconsistent vestige on a glass-filled part, that’s usually a material-to-blade mismatch before it’s a maintenance problem. And gate type itself changes the trim approach – a submarine gate and a tab gate don’t degate the same way, so the blade decision starts upstream at the mold design.

Getting It Right the First Time

Degating is the deepest, most specific thing >ASS< builds – custom stations and nipper hardware engineered around the actual gate and material in front of them. The two failure points that show up again and again are the same ones covered here: gate vestige that drifts because the trim step is inconsistent, and tooling that adds cycle time instead of saving it because nobody ran the payload or force numbers before specifying it.

The nest is what gets underestimated. Custom-designed, 3D printed part nests are what let you hit a clean cut with the smallest vestige possible, over and over, instead of just on the first hundred parts.

If you’re still degating by hand, or the nipper blades on your current setup are wearing faster than they should, talk to our engineering team about your specific gate and material. Bring the part, bring the press, and we’ll spec the nipper, sprue gripper, or station that actually fits it – contact us to get started.