Why Your Magnetic Conveyor Is Not Picking Up Parts

A magnetic conveyor is designed to move ferrous material with consistency and reliability. When it stops picking up parts, production can be affected immediately. The issue is usually not random. In most cases, poor pickup is tied to material type, part geometry, conveyor setup, surface condition, or wear inside the conveyor.

The key is to diagnose the problem based on how a magnetic conveyor actually works.

Unlike a mechanical conveyor, a magnetic conveyor does not physically grab parts with cleats, belts, or flights. It uses internal magnets that travel underneath a sealed slider surface. As the magnets move, ferrous parts above the surface are attracted to the magnetic field and carried along the conveyor path.

If the material is not magnetic, if the part is too far from the magnets, or if the conveyor was not designed for the part being moved, pickup performance can suffer.

Start With the Material

The first thing to verify is the material itself.

Magnetic conveyors only work with ferrous materials such as carbon steel, iron, and certain magnetic stainless steels. If the parts are aluminum, brass, copper, plastic, or most grades of stainless steel, they will not respond to the magnetic field.

In mixed-material environments, this can make the conveyor appear inconsistent. Some parts may move while others stay behind. In that case, the conveyor may be working correctly, but the material mix has changed.

Before assuming there is a conveyor issue, confirm that the parts being run are actually magnetic.

Check Part Thickness and Weight

Part size and mass also affect pickup.

Very thin parts may not provide enough material for the magnetic field to influence effectively, especially if there is any separation between the part and the conveyor surface. On the other end, very heavy parts may exceed the holding strength of the magnets, particularly on inclines or at higher conveyor speeds.

A magnetic conveyor needs enough magnetic attraction to do two things:

1. Pull the part to the conveyor surface
2. Hold the part securely while it moves

If the part is too light, too thin, too heavy, or too awkwardly shaped, pickup may become inconsistent.

Look for Air Gaps

Air gaps are one of the most common causes of poor magnetic conveyor performance.

Magnetic strength drops quickly as distance increases. If there is too much space between the part and the internal magnets, the conveyor may not have enough pull to pick up or move the part effectively.

Common causes of air gaps include:

• Dirt, scale, chips, or fines on the conveyor surface
• Oil or coolant buildup
• A worn or damaged slider bed
• A replacement slider surface that is thicker than the original
• Parts that do not sit flat on the conveyor
• Material bridging over the conveyor instead of contacting the surface

Even a small increase in distance can make a noticeable difference. If the conveyor used to work well and now struggles, check whether anything has changed between the part and the magnet face.

Clean the Conveyor Surface

Contamination can also reduce pickup.

Oil, coolant, fines, chips, dust, and scale can build up on the slider surface over time. This buildup creates a barrier between the part and the magnetic field. In some cases, it can also cause parts to slide, float, or sit unevenly on the surface.

A magnetic conveyor does not need perfect conditions to work, but the surface should be kept reasonably clean. If pickup has gradually gotten worse, surface buildup should be one of the first things inspected.

Evaluate the Part Shape

Part geometry has a major impact on how well a magnetic conveyor performs.

Flat parts generally work well because they maintain consistent contact with the conveyor surface. Irregular parts can be more difficult. Curved, round, twisted, nested, or oddly shaped parts may not stay fully engaged with the magnetic field.

This can lead to several problems:

• Parts rocking on the conveyor surface
• Parts losing contact during movement
• Parts sliding instead of traveling with the magnets
• Parts nesting or locking together
• Parts falling away at inclines, curves, or transitions

The issue may not be magnetic strength alone. It may be how the part physically contacts the conveyor.

Watch for Long Parts Spanning Multiple Magnets

Long parts can create a different type of problem.

If a part is long enough to span across multiple magnet positions at the same time, one magnet may be pulling the part forward while another magnet is holding it back. This can cause the part to stall, chatter, or hesitate instead of moving smoothly.

In this situation, the conveyor may appear to have a pickup issue, but the part is actually being held by competing magnetic fields. Magnet spacing, part length, conveyor speed, and part orientation all matter in these applications.

Review Loading Conditions

How material is fed onto the conveyor also matters.

If too much material is loaded at once, parts can stack, overlap, or bridge across the conveyor surface. When this happens, only the bottom layer may be influenced by the magnets. Parts sitting on top of other parts may not move consistently.

Overloading can make a properly designed conveyor look like it is underperforming.

For best results, material should be fed in a controlled and reasonably even flow. If parts are dumped onto the conveyor in heavy surges, a feeder, chute change, or metering device may be needed upstream.

Check Conveyor Speed and Incline

Speed and incline can also affect magnetic hold.

The faster the conveyor runs, the less time the magnet has to engage and control each part. On an incline, the conveyor also has to overcome gravity while keeping the part attached to the slider surface.

A part that moves well on a horizontal conveyor may struggle on a steep incline if the magnet strength, part contact, and conveyor speed are not matched correctly.

If pickup problems happen mainly on the incline or near a transition point, the issue may be related to the application setup rather than the conveyor itself.

Inspect for Internal Wear

Magnetic conveyors are low maintenance, but they are not maintenance free.

Over time, chains, sprockets, wear tracks, slider beds, and internal components can wear. If the magnet assemblies are not traveling smoothly or staying properly aligned beneath the surface, performance can drop.

Signs of internal wear may include:

• Inconsistent movement
• Unusual noise
• Jerky magnet travel
• Parts moving in some areas but not others
• Reduced pickup compared to previous performance

If the conveyor has been in service for a long time and the application has not changed, internal inspection may be needed.

Confirm the Conveyor Was Designed for the Current Application

Sometimes the conveyor is working as designed, but the application has changed.

This can happen when a conveyor originally built for one part is later used for a different part. The new part may be heavier, thinner, longer, less magnetic, more irregular, or loaded at a higher rate than the original design allowed for.

Important design factors include:

• Part material
• Part weight
• Part thickness
• Part length
• Required conveyor angle
• Loading rate
• Magnet strength
• Magnet spacing
• Slider bed thickness
• Conveyor speed

If the conveyor was not designed around the current part, pickup issues may not be caused by failure. They may be caused by a mismatch between the conveyor and the application.

When the Conveyor Is Not the Problem

In many cases, the magnetic conveyor has not failed. The issue is that something has changed.

The material may be different. The parts may be heavier or shaped differently. The conveyor surface may be dirty. The feed rate may have increased. A replacement wear surface may have created a larger air gap. Any of these changes can reduce pickup performance.

When diagnosing the issue, start with the basics:

• Is the material ferrous?
• Is the part making good contact with the conveyor surface?
• Is there buildup or contamination?
• Has the part size, weight, or shape changed?
• Is the conveyor being overloaded?
• Are the internal components still moving correctly?
• Was the conveyor designed for this part?

Answering these questions will usually point to the root cause.

Final Takeaway

A magnetic conveyor is a reliable solution when it is matched correctly to the application. When it is not picking up parts, the problem usually comes back to material type, air gap, part geometry, loading conditions, wear, or system design.

The best approach is to step back and evaluate the fundamentals. Confirm the material is magnetic, make sure the part can contact the conveyor surface, check for buildup or wear, and review whether the conveyor is still being used for the application it was originally designed to handle.

In most cases, correcting one of these factors will restore performance and keep the conveyor running as intended.

FAQ

Why is my magnetic conveyor not picking up parts?

The most common causes are non-ferrous material, poor contact with the conveyor surface, excess air gap, surface buildup, overloaded conditions, or a part that is too heavy, too thin, or shaped poorly for the conveyor.

Do magnetic conveyors work with stainless steel?

Some stainless steels are magnetic, but many are not. If the stainless part does not respond to a magnet, a magnetic conveyor will not move it effectively.

Can oil or coolant affect magnetic conveyor pickup?

Yes. Oil, coolant, fines, chips, and scale can create a barrier between the part and the conveyor surface. This increases the effective air gap and can reduce pickup performance.

Why do some parts move while others stay behind?

This usually means the material, size, shape, or contact area is inconsistent. In mixed-material applications, ferrous parts may move while non-ferrous parts remain behind.

Can a magnetic conveyor lose strength over time?

Magnets typically do not lose strength under normal conditions, but performance can drop if there is internal wear, damaged components, increased air gap, contamination, or exposure to conditions outside the conveyor’s design limits.

What should I check first if pickup performance drops?

Start by confirming the material is ferrous. Then check the conveyor surface for buildup, inspect for air gaps, review the part size and shape, and confirm the loading conditions have not changed.

Written by the engineering and applications team at Storch Magnetics, specializing in magnetic conveyors and industrial magnetic solutions.