TAZ 5 Wavy Base Layer

I am having a problem getting an even first layer print on my TAZ 5 as you can see in the attached photo of a print that I cancelled. The wavy pattern always seems to start along the edges that are parallel to the X axis (bottom and top of photo). I am trying to obtain a print that has a relatively flat and smooth surface approx 260mm (X) by 170mm (Y) at layer 1.5 mm on the Z axis, but the rough first layer seems to preclude this.

I have the problem with ABS, ABS/Polycarbonate alloy and HIPS. I have used Cura and Simplify 3D control software. I have experimented with different Z Stop settings, first layer extrusion multipliers, layer heights and extrusion widths. I have levelled the bed before each print. I noticed some play in the Y axis bearings and replaced them with LB10UU bearings. I now notice some play in the three X axis bearings (on the print head carrier) and have ordered replacements for them.

Should I be trying something else? Any feedback is appreciated!

My first guess is that your Z axis is a little low, try raising it just a hair.

Also possibly over extruding, turn extrusion multiplier down a little.

I have similar problem with my TAZ 6 but only occasionally. I think it is caused by plastic residue on the nozzle which affects the bed leveling so that it thinks the bed is lower than it is. When I clean the nozzle everything is fine. Try making the gap between your bed and nozzle a bit larger as was already suggested.